Access schemes for activity-based data protection in a memory device

ABSTRACT

Methods, systems, and devices for activity-based data protection in a memory device are described. In one example, a memory device may include a set memory sections each having memory cells configured to be selectively coupled with access lines of the respective memory section. A method of operating the memory device may include determining a quantity of access operations performed on a set of sections of a memory device, selecting at least one of the sections for a voltage adjustment operation based on the determined quantity of access operations, and performing the voltage adjustment operation on the selected section. The voltage adjustment operation may include applying an equal voltage to opposite terminals of the memory cells, which may allow built-up charge, such as leakage charge accumulating from access operations of the selected memory section, to dissipate from the memory cells of the selected section.

CROSS REFERENCES

The present application for patent is a continuation of U.S. patentapplication Ser. No. 16/104,693 by Villa et al., entitled “ACCESSSCHEMES FOR ACTIVITY-BASED DATA PROTECTION IN A MEMORY DEVICE,” filedAug. 17, 2018, which is related to the following co-pending U.S. patentapplication: “ACCESS SCHEMES FOR SECTION-BASED DATA PROTECTION IN AMEMORY DEVICE,” by Fackenthal et al., having Attorney Docket No. P269(88231.0734), filed concurrently herewith, assigned to the assigneehereof, and each of which is expressly incorporated by reference herein.

BACKGROUND

The following relates generally to memory systems and more specificallyto access schemes for activity-based data protection in a memory device.

Memory devices are widely used to store information in variouselectronic devices such as computers, wireless communication devices,cameras, digital displays, and the like. Information is stored byprograming different states of a memory device. For example, binarymemory devices have two logic states, often denoted by a logic “1” or alogic “0”. In other memory devices, more than two logic states may bestored. To access the stored information, a component of the electronicdevice may read, or sense, the stored logic state in the memory device.To store information, a component of the electronic device may write, orprogram, the logic state in the memory device.

Various types of memory devices exist, including those that employmagnetic hard disks, random access memory (RAM), read only memory (ROM),dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), ferroelectric RAM(FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phasechange memory (PCM), and others. Memory devices may be volatile ornon-volatile. Non-volatile memory, such as PCM and FeRAM, may maintainstored logic states for extended periods of time even in the absence ofan external power source. Volatile memory devices, such as DRAM, maylose stored logic states over time unless they are periodicallyrefreshed by a power source. In some cases, non-volatile memory may usesimilar device architectures as volatile memory but may havenon-volatile properties by employing such physical phenomena asferroelectric capacitance or different material phases.

Improving memory devices, may include increasing memory cell density,increasing read/write speeds, increasing reliability, increasing dataretention, reducing power consumption, or reducing manufacturing costs,among other metrics. In some cases, access operations on selected memorycells of a section of a memory device may cause charge to accumulate onnon-selected memory cells of the section of the memory device, which maycontribute to a loss of data stored in the non-selected memory cells.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example memory device that supports access schemesfor activity-based data protection in a memory device in accordance withexamples of the present disclosure.

FIG. 2 illustrates an example circuit that supports access schemes foractivity-based data protection in a memory device in accordance withexamples of the present disclosure.

FIG. 3 illustrates an example of non-linear electrical properties withhysteresis plots for a memory cell that supports access schemes foractivity-based data protection in a memory device in accordance withexamples of the present disclosure.

FIG. 4 illustrates an example of a circuit that supports access schemesfor activity-based data protection in a memory device in accordance withexamples of the present disclosure.

FIG. 5 shows a timing diagram illustrating operations of example accessschemes for activity-based data protection in a memory device inaccordance with various embodiments of the present disclosure.

FIGS. 6A and 6B show flowcharts illustrating a method or methods thatmay support access schemes for section-based data protection in a memorydevice in accordance with various embodiments of the present disclosure.

FIG. 7 illustrates an example of a state diagram that may support accessschemes for activity-based data protection in a memory device inaccordance with various embodiments of the present disclosure

FIG. 8 shows a block diagram of a memory device that may support accessschemes for activity-based data protection in a memory device inaccordance with various embodiments of the present disclosure.

FIG. 9 shows a block diagram of a memory controller that may supportaccess schemes for activity-based data protection in a memory device inaccordance with various embodiments of the present disclosure.

FIG. 10 shows a diagram of a system including a device that may supportaccess schemes for activity-based data protection in a memory device inaccordance with various embodiments of the present disclosure.

DETAILED DESCRIPTION

The logic state of memory cells may be maintained by performing accessschemes for activity-based data protection in a memory device inaccordance with aspects of the present disclosure. For example, a memorydevice may be divided into a number of memory sections. At least some ifnot each of the memory sections may include a set of memory cellscoupled with or between a digit line of the memory section and a plateline, or a common plate, or other common node of the memory section(e.g., node common to all the memory cells of the memory section). Eachof the memory cells of a memory section may include or be otherwiseassociated with a cell selection component configured to selectivelycouple the memory cell with the associated digit line of the memorysection. In some examples, each of the cell selection components may becoupled with (e.g., at a control node, a control terminal, a selectionnode, or selection terminal of the cell selection component) one of aset of word lines of the memory section, which may be used to activateor deactivate the particular cell selection component.

Access operations (e.g., read operations, write operations, rewriteoperations, refresh operations, or combinations thereof) may beperformed on selected memory cells (e.g., a memory cell selected orotherwise identified for a respective access operation) of a memorysection. In some examples, an access operation may be associated withbiasing a plate line or a digit line of an associated memory section.During an access operation, the cell selection component for a selectedmemory cell may be activated such that the selected memory cell may beselectively coupled with the digit line and the plate line of theassociated memory section. Thus, a signal associated with the accessoperation (e.g., a voltage associated with the access operation, acharge associated with the access operation, a current associated withthe access operation) may pass to, from, or through the selected memorycell as a result of the biasing of the digit line or the plate line ofthe memory section for the access operation.

Although the cell selection components of non-selected memory cells(e.g., cells of a memory section not selected or otherwise identifiedfor the access operation of the memory section) may be deactivated,charge (e.g., leakage charge) may flow through deactivated cellselection components. For example, when a digit line or a plate line ofa memory section is biased at a voltage associated with the accessoperation on a selected memory cell, a difference in voltage between thedigit line or the plate line and a non-selected memory cell (e.g., anintermediate node of a non-selected memory cell) may cause charge toflow across the deactivated cell selection component and to or from thenon-selected memory cell (e.g., during the access operation on theselected memory cell). Other mechanisms may also result in a flow ofleakage charge, such as a coupling between memory cells that permitsleakage charge to flow from a storage element of one memory cell to thestorage element of another memory cell (e.g., passing throughdeactivated cell selection components, passing around deactivated cellselection components, passing from an intermediate node of one memorycell to an intermediate node of another memory cell).

In some examples, the leakage charge may cause a bias (e.g., a non-zerobias or voltage) across a memory cell that would otherwise not bepresent (e.g., a cell that would otherwise have an equalized bias orvoltage). Such a leakage charge or non-zero bias may accumulate on orfrom non-selected memory cells of a memory section in successive accessoperations of the memory section, which, in some examples, may cause aloss of data stored in memory cells of the memory section.

In accordance with examples of the present disclosure, operations may beperformed on memory sections of a memory device to enable or otherwisesupport the dissipation of accumulated leakage charge or bias frommemory cells of the memory sections. For example, the cell selectioncomponents of one or more memory cells (e.g., all of the memory cells)of a selected memory section may be activated (e.g., by activating or“raising” one or more word lines associated with the selected memorysection, by activating all word lines associated with the selectedmemory section).

While the cell selection components of the selected memory section areactivated (e.g., “turned on”), the associated digit lines of theselected memory section and plate lines, a common plate, or anothercommon node of the selected memory section may be coupled with voltagesources that support the dissipation of accumulated leakage charge orbias. For example, digit lines and plate lines of a memory sectionselected for such operations may be coupled with a same voltage source,coupled with different voltage sources having the same voltage, orcoupled with voltage sources having voltages that otherwise support thedissipation of leakage charge or bias accumulated at memory cells of theselected memory section. In some examples, the described operations of amemory section associated with such a dissipation of leakage charge orbias may be referred to as a voltage adjustment operation (e.g., adissipation operation, an equalization operation) for the memorysection. The operations may be described as, or be part of a WordlineOnly Refresh (WOR) operation.

The selection of a memory section for such operations may be based on anaccess history of a set of sections of the memory device. For example, amemory device may include a counter for each of the set sections of thememory device, where a respective counter is incremented each time thememory section is accessed (e.g., read, written, rewritten, refreshed,precharged). The memory device may determine to perform a voltageadjustment operation (e.g., based on a timer, based on a periodicinterval, based on an aperiodic interval), and then select the memorysection having the highest counter value. In other words, the memorydevice may select, for a voltage adjustment operation, a memory sectionhaving the highest number of access operations since a prior voltageadjustment operation on the memory section. The memory device may thenperform the voltage adjustment operation on the selected memory section,and reset the counter for the selected memory section so that adifferent memory section may be associated with the highest number ofaccess operations since a prior voltage adjustment operation. Thus, amemory device may perform voltage adjustment operations on memorysections associated with the highest occurrence of access operations(e.g., most-frequently accessed sections).

The dissipation of leakage charge or bias accumulated at most-frequentlyaccessed sections may prevent or reduce the degradation of a logic statestored by memory cells of those memory sections. For example,ferroelectric memory cells of a memory section may operate based on anon-linear polarization behavior (e.g., an ability to store charge in anabsence of an applied electrical field). In other words, as one example,a polarized ferroelectric memory storage element may store charge evenwhen no electric field is actively applied across the memory cell (e.g.,in an equalized state, in a standby state). Leakage charge or a non-zerobias may cause a degradation or loss of polarization, however, and sucha degradation of polarization may be exacerbated by leakage charge orbias accumulating from successive access operations performed at amemory section. By performing the operations described herein (e.g.,voltage adjustment operations, dissipation operations, equalizationoperations), leakage charge or non-zero bias accumulated atferroelectric memory cells of a memory section, for example, may bedissipated after access operations performed on the memory section,which may mitigate or prevent the accumulation of leakage charge or biasacross successive access operations of the memory section, and improvethe ability of a memory device to maintain stored data. Further, byselecting a most-frequently accessed memory section for such operations,a memory device may operate in a more-targeted manner than when suchoperations are performed without considering a frequency of accessoperations on respective memory sections.

Features of the disclosure introduced above are further described withreference to FIGS. 1 through 3 in the context of memory arrays, memorycircuits, and memory cell behaviors that support access schemes foractivity-based data protection in a memory device. Specific examples arethen described with reference to FIGS. 4 and 5, which illustrate aparticular circuit and an associated timing diagram that support accessschemes for activity-based data protection in a memory device. Furtherexamples of methods and circuits that may support the describedoperations are described with reference to FIGS. 6 through 8. These andother features of the disclosure are further described with respect toFIGS. 9 through 11, which illustrate apparatus and system diagrams thatsupport access schemes for activity-based data protection in a memorydevice.

FIG. 1 illustrates an example memory device 100 that supports accessschemes for activity-based data protection in a memory device inaccordance with various embodiments of the present disclosure. Thememory device 100 may also be referred to as an electronic memoryapparatus. The memory device 100 may include memory cells 105 that areprogrammable to store different logic states. In some cases, a memorycell 105 may be programmable to store two logic states, denoted a logic0 and a logic 1. In some cases, a memory cell 105 may be programmable tostore more than two logic states. In some examples, the memory cells 105may include a capacitive memory element, a ferroelectric memory element,a resistive element, a self-selecting memory element, or a combinationthereof.

The set of memory cells 105 may be part of a memory section 110 of thememory device 100 (e.g., including an array of memory cells 105), wherein some examples a memory section 110 may refer to a contiguous tile ofmemory cells 105 (e.g., a contiguous set of elements of a semiconductorchip). In some examples, a memory section 110 may refer to the smallestset of memory cells 105 that may be biased in an access operation, or asmallest set of memory cells 105 that share a common node (e.g., acommon plate line, a set of plate lines that are biased to a commonvoltage). Although only a single memory section 110 of the memory device100 is shown, various examples of a memory device in accordance with thepresent disclosure may have a set of memory sections 110. In oneillustrative example, a memory device 100 may include 32 “banks” andeach bank may include 32 sections. Thus, a memory device 100 accordingto the illustrative example may include 1,024 memory sections 110.

In some examples, a memory cell 105 may store an electric chargerepresentative of the programmable logic states (e.g., storing charge ina capacitor, capacitive memory element, capacitive storage element). Inone example, a charged and uncharged capacitor may represent two logicstates, respectively. In another example, a positively charged andnegatively charged capacitor may represent two logic states,respectively. DRAM or FeRAM architectures may use such designs, and thecapacitor employed may include a dielectric material with linear orpara-electric polarization properties as an insulator. In some examples,different levels of charge of a capacitor may represent different logicstates (e.g., supporting more than two logic states in a respectivememory cell 105). In some examples, such as FeRAM architectures, amemory cell 105 may include a ferroelectric capacitor having aferroelectric material as an insulating (e.g., non-conductive) layerbetween terminals of the capacitor. Different levels of polarization ofa ferroelectric capacitor may represent different logic states (e.g.,supporting two or more logic states in a respective memory cell 105).Ferroelectric materials have non-linear polarization propertiesincluding those discussed in further detail with reference to FIG. 3.

In some examples, a memory cell 105 may include a material portion,which may be referred to as a memory element, a memory storage element,a self-selecting memory element, or a self-selecting memory storageelement. The material portion may have a variable and configurableelectrical resistance that is representative of different logic states.

For example, a material that can take the form of a crystalline atomicconfiguration or an amorphous atomic configuration (e.g., able tomaintain either a crystalline state or an amorphous state over anambient operating temperature range of the memory device 100) may havedifferent electrical resistances depending on the atomic configuration.A more-crystalline state of the material (e.g., a single crystal, acollection of a relatively large crystal grains that may besubstantially crystalline) may have a relatively low electricalresistance, and may alternatively be referred to as a “SET” logic state.A more-amorphous state of the material (e.g., an entirely amorphousstate, some distribution of relatively small crystal grains that may besubstantially amorphous) may have a relatively high electricalresistance, and may alternatively be referred to as a “RESET” logicstate. Thus, a voltage applied to such a memory cell 105 may result indifferent current flow depending on whether the material portion of thememory cell 105 is in the more-crystalline or the more-amorphous state.Accordingly, the magnitude of the current resulting from applying a readvoltage to the memory cell 105 may be used to determine a logic statestored by memory cell 105.

In some examples, a memory element may be configured with various ratiosof crystalline and amorphous areas (e.g., varying degrees of atomicorder and disorder) that may result in intermediate resistances, whichmay represent different logic states (e.g., supporting two or more logicstates in a respective memory cell 105). Further, in some examples, amaterial or a memory element may have more than two atomicconfigurations, such as an amorphous configuration and two differentcrystalline configurations. Although described herein with reference toan electrical resistance of different atomic configurations, a memorydevice may use some other characteristic of a memory element todetermine a stored logic state corresponding to an atomic configuration,or combination of atomic configurations.

In some cases, a memory element in a more-amorphous state may beassociated with a threshold voltage. In some examples, electricalcurrent may flow through a memory element in the more-amorphous statewhen a voltage greater than the threshold voltage is applied across thememory element. In some examples, electrical current may not flowthrough a memory element in the more-amorphous state when a voltage lessthan the threshold voltage is applied across the memory element. In somecases, a memory element in a more-crystalline state may not beassociated with a threshold voltage (e.g., may be associated with athreshold voltage of zero). In some examples, electrical current mayflow through a memory element in the more-crystalline state in responseto a non-zero voltage across the memory element.

In some cases, a material in both the more-amorphous state and themore-crystalline state may be associated with threshold voltages. Forexample, self-selecting memory may enhance differences in a thresholdvoltage of a memory cell between different programmed states (e.g., byway of different compositional distributions). The logic state of amemory cell 105 having such a memory element may be set by heating thememory element to a temperature profile over time that supports forminga particular atomic configuration, or combination of atomicconfigurations.

A memory device 100 may include a three-dimensional (3D) memory array,where a plurality of two-dimensional (2D) memory arrays (e.g., decks,levels) are formed on top of one another. In various examples, sucharrays may be divided into a set of memory sections 110, where eachmemory section 110 may be arranged within a deck or level, distributedacross multiple decks or levels, or any combination thereof. Sucharrangements may increase the number of memory cells 105 that may beplaced or created on a single die or substrate as compared with 2Darrays, which in turn may reduce production costs or increase theperformance of a memory device 100, or both. The decks or levels may beseparated by an electrically insulating material. Each deck or level maybe aligned or positioned so that memory cells 105 may be approximatelyaligned with one another across each deck, forming a stack of memorycells 105.

In the example of memory device 100, each row of memory cells 105 of thememory section 110 may be coupled with one of a set of first accesslines 120 (e.g., a word line (WL), such as one of WL₁ through WL_(M)),and each column of memory cells 105 may be coupled with one of a set ofsecond access lines 130 (e.g., a digit line (DL), such as one of DL₁through DL_(N)). In some examples, a row of memory cells 105 of adifferent memory section 110 (not shown) may be coupled with one of adifferent plurality of first access lines 120 (e.g., a word linedifferent from WL₁ through WL_(M)), and a column of memory cells 105 ofthe different memory section 110 may be coupled with one of a differentplurality of second access lines 130 (e.g., a digit line different fromDL₁ through DL_(N)). In some cases, first access lines 120 and secondaccess lines 130 may be substantially perpendicular to one another inthe memory device 100 (e.g., when viewing a plane of a deck of thememory device 100, as shown in FIG. 1). References to word lines and bitlines, or their analogues, are interchangeable without loss ofunderstanding or operation.

In general, one memory cell 105 may be located at the intersection of(e.g., coupled with, coupled between) an access line 120 and an accessline 130. This intersection may be referred to as an address of a memorycell 105. A target or selected memory cell 105 may be a memory cell 105located at the intersection of an energized or otherwise selected accessline 120 and an energized or otherwise selected access line 130. Inother words, an access line 120 and an access line 130 may be energizedor otherwise selected to access (e.g., read, write, rewrite, refresh) amemory cell 105 at their intersection. Other memory cells 105 that arein electronic communication with (e.g., connected to) the same accessline 120 or 130 may be referred to as untargeted or non-selected memorycells 105.

In some architectures, the logic storing component (e.g., a capacitivememory element, a ferroelectric memory element, a resistive memoryelement, other memory element) of a memory cell 105 may be electricallyisolated from a second access line 130 by a cell selection component,which, in some examples, may be referred to as a switching component ora selector device. A first access line 120 may be coupled with the cellselection component (e.g., via a control node or terminal of the cellselection component), and may control the cell selection component ofthe memory cell 105. For example, the cell selection component may be atransistor and the first access line 120 may be coupled with a gate ofthe transistor (e.g., where a gate node of the transistor may be acontrol node of the transistor). Activating the first access line 120 ofa memory cell 105 may result in an electrical connection or closedcircuit between the logic storing component of the memory cell 105 andits corresponding second access line 130. The second access line 130 maythen be accessed to read or write the memory cell 105.

In some examples, memory cells 105 of the memory section 110 may also becoupled with one of a plurality of third access lines 140 (e.g., a plateline (PL), such as one of PL₁ through PL_(N)). Although illustrated asseparate lines, in some examples, the plurality of third access lines140 may represent or be otherwise functionally equivalent with a commonplate line, a common plate, or other common node of the memory section110 (e.g., a node common to each of the memory cells 105 in the memorysection 110), or other common node of the memory device 100. In someexamples, the plurality of third access lines 140 may couple memorycells 105 with one or more voltage sources for various sensing and/orwriting operations including those described herein. For example, when amemory cell 105 employs a capacitor for storing a logic state, a secondaccess line 130 may provide access to a first terminal or a first plateof the capacitor, and a third access line 140 may provide access to asecond terminal or a second plate of the capacitor (e.g., a terminalassociated with an opposite plate of the capacitor as opposed to thefirst terminal of the capacitor, a terminal otherwise on the oppositeside of a capacitance from the first terminal of the capacitor). In someexamples, memory cells 105 of a different memory section 110 (not shown)may be coupled with one of a different plurality of third access lines140 (e.g., a set of plate lines different from PL₁ through PL_(N), adifferent common plate line, a different common plate, a differentcommon node).

The plurality of third access lines 140 may be coupled with a platecomponent 145, which may control various operations such as activatingone or more of the plurality of third access lines 140, or selectivelycoupling one or more of the plurality of third access lines 140 with avoltage source or other circuit element. Although the plurality of thirdaccess lines 140 of the memory device 100 are shown as substantiallyparallel with the plurality of second access lines 130, in otherexamples, a plurality of third access lines 140 may be substantiallyparallel with the plurality of first access lines 120, or in any otherconfiguration.

Although the access lines described with reference to FIG. 1 are shownas direct lines between memory cells 105 and coupled components, accesslines may include other circuit elements, such as capacitors, resistors,transistors, amplifiers, voltage sources, switching components,selection components, and others, which may be used to support accessoperations including those described herein. In some examples, anelectrode may be coupled with (e.g., between) a memory cell 105 and anaccess line 120, or with (e.g., between) a memory cell 105 and an accessline 130. The term electrode may refer to an electrical conductor, orother electrical interface between components, and in some cases, may beemployed as an electrical contact to a memory cell 105. An electrode mayinclude a trace, wire, conductive line, conductive layer, conductivepad, or the like, that provides a conductive path between elements orcomponents of memory device 100.

Access operations such as reading, writing, rewriting, and refreshingmay be performed on a memory cell 105 by activating or selecting a firstaccess line 120, a second access line 130, and/or a third access line140 coupled with the memory cell 105, which may include applying avoltage, a charge, or a current to the respective access line. Accesslines 120, 130, and 140 may be made of conductive materials, such asmetals (e.g., copper (Cu), silver (Ag), aluminum (Al), gold (Au),tungsten (W), titanium (Ti)), metal alloys, carbon, or other conductiveor semi-conductive materials, alloys, or compounds. Upon selecting amemory cell 105, a resulting signal may be used to determine the logicstate stored by the memory cell 105. For example, a memory cell 105 witha capacitive memory element storing a logic state may be selected, andthe resulting flow of charge via an access line and/or resulting voltageof an access line may be detected to determine the programmed logicstate stored by the memory cell 105.

Accessing memory cells 105 may be controlled through a row component 125(e.g., a row decoder), a column component 135 (e.g., a column decoder),or a plate component 145 (e.g., a plate driver), or a combinationthereof. For example, a row component 125 may receive a row address fromthe memory controller 170 and activate the appropriate first access line120 based on the received row address. Similarly, a column component 135may receive a column address from the memory controller 170 and activatethe appropriate second access line 130. Thus, in some examples, a memorycell 105 may be accessed by activating a first access line 120 and asecond access line 130. In some examples, such access operations may beaccompanied by a plate component 145 biasing one or more of the thirdaccess lines 140 (e.g., biasing one of the third access lines 140 of thememory section 110, biasing all of the third access line 140 of thememory section, biasing a common plate line of the memory section 110 ormemory device 100, biasing a common node of the memory section 110 ormemory device 100), which may be referred to as “moving the plate” ofmemory cells 105, the memory section 110, or the memory device 100.

In some examples, the memory controller 170 may control the operation(e.g., read operations, write operations, rewrite operations, refreshoperations, discharge operations, voltage adjustment operations,dissipation operations, equalization operations) of memory cells 105through the various components (e.g., row component 125, columncomponent 135, plate component 145, sense component 150). In some cases,one or more of the row component 125, the column component 135, theplate component 145, and the sense component 150 may be co-located orotherwise included with the memory controller 170. The memory controller170 may generate row and column address signals to activate a desiredaccess line 120 and access line 130. The memory controller 170 may alsogenerate or control various voltages or currents used during theoperation of memory device 100. For example, the memory controller 170may apply a discharge or equalization voltage to one or more of anaccess line 120, an access line 130, or an access line 140 of a memorysection 110 after accessing one or more memory cells 105. Although onlya single memory controller 170 is shown, other examples of a memorydevice 100 may have more than one memory controller 170 (e.g., a memorycontroller 170 for each of a set of memory sections 110 of a memorydevice, a memory controller 170 for each of a number of subsets ofmemory sections 110 of a memory device 100, a memory controller 170 foreach of a set of chips of a multi-chip memory device 100, a memorycontroller 170 for each of a set of banks of a multi-bank memory device100, a memory controller 170 for each core of a multi-core memory device100, or any combination thereof), where different memory controllers 170may perform the same functions and/or different functions.

Although the memory device 100 is illustrated as including a single rowcomponent 125, a single column component 135, and a single platecomponent 145, other examples of a memory device 100 may includedifferent configurations to accommodate a set of memory sections 110.For example, in various memory devices 100 a row component 125 may beshared among a set of memory sections 110 (e.g., having subcomponentscommon to all of the set of memory sections 110, having subcomponentsdedicated to respective ones of the set of memory sections 110), or arow component 125 may be dedicated to one memory section 110 of a set ofmemory sections 110. Likewise, in various memory devices 100, a columncomponent 135 may be shared among a set of memory sections 110 (e.g.,having subcomponents common to all of the set of memory sections 110,having subcomponents dedicated to respective ones of the set of memorysections 110), or a column component 135 may be dedicated to one memorysection 110 of a set of memory sections 110. Additionally, in variousmemory devices 100, a plate component 145 may be shared among a set ofmemory sections 110 (e.g., having subcomponents common to all of the setof memory sections 110, having subcomponents dedicated to respectiveones of the set of memory sections 110), or a plate component 145 may bededicated to one memory section 110 of a set of memory sections 110.

In general, the amplitude, shape, or duration of an applied voltage,current, or charge may be adjusted or varied, and may be different forthe various operations discussed in operating the memory device 100.Further, one, multiple, or all memory cells 105 within memory device 100may be accessed simultaneously. For example, multiple or all memorycells 105 of memory device 100 may be accessed simultaneously during areset operation in which all memory cells 105, or a group of memorycells 105 (e.g., the memory cells 105 of a memory section 110), are setto a single logic state.

A memory cell 105 may be read (e.g., sensed) by a sense component 150when the memory cell 105 is accessed (e.g., in cooperation with thememory controller 170) to determine a logic state stored by the memorycell 105. For example, the sense component 150 may be configured tosense a current or charge through the memory cell 105, or a voltageresulting from coupling the memory cell 105 with the sense component 150or other intervening component (e.g., a signal development componentbetween the memory cell 105 and the sense component 150), responsive toa read operation. The sense component 150 may provide an output signalindicative of the logic state stored by the memory cell 105 to one ormore components (e.g., to the column component 135, the input/outputcomponent 160, the memory controller 170). In various memory devices100, a sense component 150 may be shared among a set of memory sections110 (e.g., having subcomponents common to all of the set of memorysections 110, having subcomponents dedicated to respective ones of theset of memory sections 110), or a sense component 150 may be dedicatedto one memory section 110 of a set of memory sections 110.

In some examples, during or after accessing a memory cell 105, the logicstorage portion of memory cell 105 may discharge, or otherwise permitelectrical charge or current to flow via its corresponding access lines120, 130, or 140. Such charge or current may result from biasing, orapplying a voltage, to the memory cell 105 from one or more voltagesources or supplies (not shown) of the memory device 100, where suchvoltage sources or supplies may be part of a row component 125, a columncomponent 135, a plate component 145, a sense component 150, a memorycontroller 170, or some other component (e.g., a biasing component). Insome examples, a discharge of a memory cell 105 may cause a change inthe voltage of the access line 130, which the sense component 150 maycompare to a reference voltage to determine the stored state of thememory cell 105. In some examples, a voltage may be applied to a memorycell 105 (e.g., using the corresponding access line 120 and access line130) and the presence of a resulting current may depend on the appliedvoltage and the resistance state of a memory element of the memory cell105, which the sense component 150 may use to determine the stored stateof the memory cell 105

In some examples, when a read signal (e.g., a read pulse, a readcurrent, a read voltage) is applied across a memory cell 105 with amaterial memory element storing a first logic state (e.g., a SET state,associated with a more-crystalline atomic configuration), the memorycell 105 conducts current due to the read pulse exceeding a thresholdvoltage of the memory cell 105. In response or based on this, the sensecomponent 150 may therefore detect a current through the memory cell 105as part of determining the logic state stored by the memory cell 105.When a read pulse is applied to the memory cell 105 with the memoryelement storing a second logic state (e.g., a RESET state, associatedwith a more-amorphous atomic configuration), which may occur before orafter the application of a read pulse across a memory cell 105 with amemory element storing a first logic state, the memory cell 105 may notconduct current due to the read pulse not exceeding the thresholdvoltage of the memory cell 105. The sense component 150 may thereforedetect little or no current through the memory cell 105 as part ofdetermining the stored logic state.

In some examples, a threshold current may be defined for sensing thelogic state stored by a memory cell 105. The threshold current may beset above a current that may pass through the memory cell 105 when thememory cell 105 does not threshold in response to the read pulse, butequal to or below an expected current through the memory cell 105 whenthe memory cell 105 does threshold in response to the read pulse. Forexample, the threshold current may be higher than a leakage current ofthe associated access lines 120, 130, or 140. In some examples, a logicstate stored by a memory cell 105 may be determined based on a voltage(e.g., across a shunt resistance) resulting from the current driven by aread pulse. For example, the resulting voltage may be compared relativeto a reference voltage, with a resulting voltage less than the referencevoltage corresponding to a first logic state and a resulting voltagegreater than the reference voltage corresponding to a second logicstate.

In some examples, more than one voltage may be applied when reading amemory cell 105 (e.g., multiple voltages may be applied as part of aread operation). For example, if an applied read voltage does not resultin current flow, one or more other read voltages may be applied (e.g.,until a current is detected by sense component 150). Based on assessingthe read voltage that resulted in current flow, the stored logic stateof the memory cell 105 may be determined. In some cases, a read voltagemay be ramped (e.g., smoothly increasing higher in magnitude) until acurrent flow or other condition is detected by a sense component 150. Inother cases, predetermined read voltages may be applied (e.g., apredetermined sequence of read voltages that increase higher inmagnitude in a stepwise manner) until a current is detected. In someexamples, a read current may be applied to a memory cell 105 and themagnitude of the voltage to create the read current may depend on theelectrical resistance or the total threshold voltage of the memory cell105.

A sense component 150 may include various switching components,selection components, transistors, amplifiers, capacitors, resistors, orvoltage sources to detect or amplify a difference in sensing signals(e.g., a difference between a read voltage and a reference voltage, adifference between a read current and a reference current, a differencebetween a read charge and a reference charge), which, in some examples,may be referred to as latching. In some examples, a sense component 150may include a collection of components (e.g., circuit elements) that arerepeated for each of a set of access lines 130 connected to the sensecomponent 150. For example, a sense component 150 may include a separatesensing circuit (e.g., a separate sense amplifier, a separate signaldevelopment component) for each of a set of access lines 130 coupledwith the sense component 150, such that a logic state may be separatelydetected for a respective memory cell 105 coupled with a respective oneof the set of access lines 130. In some examples, a reference signalsource (e.g., a reference component) or generated reference signal maybe shared between components of the memory device 100 (e.g., sharedamong one or more sense components 150, shared among separate sensingcircuits of a sense component 150, shared among access lines 120, 130,or 140 of a memory section 110).

The sense component 150 may be included in a device that includes thememory device 100. For example, the sense component 150 may be includedwith other read and write circuits, decoding circuits, or registercircuits of the memory that may be coupled to the memory device 100. Insome examples, the detected logic state of a memory cell 105 may beoutput through a column component 135 as an output. In some examples, asense component 150 may be part of a column component 135 or a rowcomponent 125. In some examples, a sense component 150 may be connectedto or otherwise in electronic communication with a column component 135or a row component 125.

Although a single sense component 150 is shown, a memory device 100(e.g., a memory section 110 of a memory device 100) may include morethan one sense component 150. For example, a first sense component 150may be coupled with a first subset of access lines 130 and a secondsense component 150 may be coupled with a second subset of access lines130 (e.g., different from the first subset of access lines 130). In someexamples, such a division of sense components 150 may support parallel(e.g., simultaneous) operation of multiple sense components 150. In someexamples, such a division of sense components 150 may support matchingsense components 150 having different configurations or characteristicsto particular subsets of the memory cells 105 of the memory device(e.g., supporting different types of memory cells 105, supportingdifferent characteristics of subsets of memory cells 105, supportingdifferent characteristics of subsets of access lines 130).

Additionally or alternatively, two or more sense components 150 may becoupled with a same set of access lines 130 (e.g., for componentredundancy). In some examples, such a configuration may supportmaintaining functionality to overcome a failure or otherwise pooroperation of one of the redundant sense components 150. In someexamples, such a configuration may support the ability to select one ofthe redundant sense components 150 for particular operationalcharacteristics (e.g., as related to power consumption characteristics,as related to access speed characteristics for a particular sensingoperation, as related to operating memory cells 105 in a volatile modeor a non-volatile mode).

In some memory architectures, accessing the memory cell 105 may degradeor destroy the stored logic state and rewrite or refresh operations maybe performed to return the original logic state to memory cell 105. InDRAM or FeRAM, for example, a capacitor of a memory cell 105 may bepartially or completely discharged during a sense operation, therebycorrupting the logic state that was stored in the memory cell 105. InPCM, for example, sense operations may cause a change in the atomicconfiguration of a memory cell 105, thereby changing the resistancestate of the memory cell 105. Thus, in some examples, the logic statestored in a memory cell 105 may be rewritten after an access operation.Further, activating a single access line 120, 130, or 140 may result inthe discharge of all memory cells 105 coupled with the activated accessline 120, 130, or 140. Thus, several or all memory cells 105 coupledwith an access line 120, 130, or 140 associated with an access operation(e.g., all cells of an accessed row, all cells of an accessed column)may be rewritten after the access operation.

In some examples, reading a memory cell 105 may be non-destructive. Thatis, the logic state of the memory cell 105 may not need to be rewrittenafter the memory cell 105 is read. For example, in non-volatile memorysuch as PCM, accessing the memory cell 105 may not destroy the logicstate and, thus, the memory cell 105 may not require rewriting afteraccessing. However, in some examples, refreshing the logic state of thememory cell 105 may or may not be needed in the absence or presence ofother access operations. For example, the logic state stored by a memorycell 105 may be refreshed at periodic intervals by applying anappropriate write, refresh, or equalization pulse or bias to maintainthe stored logic state. Refreshing the memory cell 105 may reduce oreliminate read disturb errors or logic state corruption due to a chargeleakage or a change in an atomic configuration of a memory element overtime.

A memory cell 105 may also be set, or written, by activating therelevant first access line 120, second access line 130, and/or thirdaccess line 140 (e.g., via a memory controller 170). In other words, alogic state may be stored in the memory cell 105. Row component 125,column component 135, or plate component 145 may accept data, forexample, via input/output component 160, to be written to the memorycells 105. In some examples, a write operation may be performed at leastin part by a sense component 150, or a write operation may be configuredto bypass a sense component 150.

In the case of a capacitive memory element, a memory cell 105 may bewritten by applying a voltage to a capacitor, and then isolating thecapacitor (e.g., isolating the capacitor from a voltage source used towrite the memory cell 105, floating the capacitor) to store a charge inthe capacitor associated with a desired logic state. In the case offerroelectric memory, a ferroelectric memory element (e.g., aferroelectric capacitor) of a memory cell 105 may be written by applyinga voltage with a magnitude high enough to polarize the ferroelectricmemory element (e.g., applying a saturation voltage) with a polarizationassociated with a desired logic state, and the ferroelectric memoryelement may be isolated (e.g., floating), or a zero net voltage or biasmay be applied across the ferroelectric memory element (e.g., grounding,virtually grounding, or equalizing a voltage across the ferroelectricmemory element). In the case of PCM, a memory element may be written byapplying a current with a profile that causes (e.g., by way of heatingand cooling) the memory element to form an atomic configurationassociated with a desired logic state.

In some examples in accordance with the present disclosure, the memorydevice 100 may include a set of memory sections 110. Each of the memorysections 110 may include a set of memory cells 105 coupled with orbetween one of a set of second access lines 130 and one of a set ofthird access lines 140 (e.g., of the respective memory section 110).Each of the memory cells 105 may include a cell selection componentconfigured to selectively couple the memory cell 105 with the associatedsecond access line 130 or the associated third access line 140 (e.g., ofthe respective memory section 110). In some examples, each of the cellselection components may be coupled (e.g., at a control node or acontrol terminal of the respective cell selection component) with arespective one of the first access lines 120 (e.g., of the memorysection 110), which may be used to activate or deactivate the particularcell selection component.

Access operations, which may include read operations, write operations,rewrite operations, refresh operations, or various combination thereof,may be performed on selected memory cells 105 of a memory section 110.In some examples, access operations may be associated with biasing thesecond access line 130 or the third access line 140 associated with aselected memory cell 105. During the access operations, cell selectioncomponents for the selected memory cell 105 may be activated, such thatselected memory cell 105 may be selectively coupled with the secondaccess line 130 or the third access line 140. Thus, signals associatedwith the access operations (e.g., a voltage associated with an accessoperation, a charge associated with an access operation, a currentassociated with an access operation) may pass to, from, or through theselected memory cell 105 as a result of the biasing of the second accessline 130 or the third access line 140 for the access operation.

Although the cell selection components of non-selected memory cells 105of a memory section 110 may be deactivated, leakage charge may flowthrough deactivated cell selection components of the memory section 110.For example, when the associated second access line 130 or third accessline 140 of the memory section 110 is biased at a voltage associatedwith an access operation on a selected memory cell 105, a difference involtage between a non-selected memory cell 105 and the second accessline 130 or the third access line 140 may cause leakage charge to flowacross the deactivated cell selection component to or from thenon-selected memory cell 105 (e.g., during the access operation on theselected memory cell). Such a leakage charge may accumulate onnon-selected memory cells 105 in successive access operations of amemory section 110, or may cause a non-zero bias or voltage toaccumulate at non-selected memory cells of a memory section 110. In someexamples, such an accumulation of leakage charge or bias may cause adegradation or loss of data stored in the memory cells 105 of the memorysection 110.

In accordance with examples of the present disclosure, operations may beperformed on a most-frequently accessed memory section 110 of a memorydevice 100 to encourage or otherwise support the dissipation ofaccumulated leakage charge or bias on memory cells 105 of the memorysection 110. For example, at particular intervals (e.g., based on avalue of a timer, based on a total number of access operations of thememory device 100), a memory controller 170 may determine to performoperations associated with the dissipation of accumulated leakage chargeof bias. Upon determining to perform such operations, the memorycontroller 170 may select one of a set of memory sections 110 of thememory device 100 upon which to perform the operations. In someexamples, the memory controller 170 may select a memory section 110based on an access history of the set of memory sections 110, such asselecting a most-frequently accessed memory section 110 (e.g., a memorysection 110 having a highest quantity of access operations performedsince a prior voltage adjustment operation on the respective memorysection 110, a memory section having a highest quantity of accessoperations performed since a memory device 100 was powered on).

The described operations to support the dissipation of accumulatedleakage charge or bias may include activating the cell selectioncomponents of each of the memory cells 105 of the selected memorysection 110 (e.g., by activating each of the first access lines 120associated with the memory section 110). For example, the operations mayinclude activating each of the first access lines 120 of the selectedmemory section 110 simultaneously or concurrently, activating a firstsubset of the first access lines 120 of the selected memory section 110during a first time period and activating a second subset of the firstaccess lines 120 of the selected memory section 110 during a second timeperiod, or activating each of the first access lines 120 of the selectedmemory section 110 in a sequential order.

While the cell selection components the memory cells 105 are activated,the second access lines 130 and the third access lines 140 of theselected memory section 110 may be coupled with voltage sources thatsupport the dissipation of accumulated leakage charge or voltage bias.For example, the second access lines 130 and the third access lines 140may be coupled with a same voltage source, or coupled with voltagesources having the same voltage, or coupled with voltage sources havingvoltages that otherwise support the dissipation of leakage charge orbias accumulated at memory cells 105 of the memory section 110.

In various examples, the described operations associated with such adissipation of leakage charge or bias may be referred to as a or avoltage adjustment operation. By performing the voltage adjustmentoperations described herein, leakage charge or voltage bias accumulatedat memory cells 105 of a most-frequently accessed memory section 110 maybe dissipated, which may mitigate or prevent the accumulation of leakagecharge across successive access operations of a memory section 110 andimprove the ability of the memory device 100 to maintain stored data.Further, by selecting a most-frequently accessed memory section 110 forsuch operations, a memory device may operate in a more targeted mannerthan when such operations are performed, for example, withoutconsidering a frequency of access operations on respective memorysections 110.

FIG. 2 illustrates an example circuit 200 that supports access schemesfor activity-based data protection in a memory device in accordance withvarious embodiments of the present disclosure. Circuit 200 may include amemory cell 105-a, which may be an example of a memory cell 105described with reference to FIG. 1. Circuit 200 may also include a senseamplifier 290, which may be a portion of a sense component 150 describedwith reference to FIG. 1. Circuit 200 may also include a word line 205,a digit line 210, and a plate line 215, which, in some examples, maycorrespond to a first access line 120, a second access line 130, and athird access line 140, respectively (e.g., of a memory section 110), asdescribed with reference to FIG. 1. In some examples, the plate line 215may be illustrative of a common plate line, a common plate, or anothercommon node for the memory cell 105-a and another memory cell 105 (notshown) of a same memory section 110. The circuit 200 may also include areference line 265 used by the sense amplifier 290 to determine a storedlogic state of the memory cell 105-a.

As illustrated in FIG. 2, the sense amplifier 290 may include a firstnode 291 and a second node 292 which, in some examples, may be coupledwith different access lines of a circuit (e.g., a signal line 260 and areference line 265 of the circuit 200, respectively) or a common accessline of a different circuit (not shown). In some examples, the firstnode 291 may be referred to as a signal node, and the second node 292may be referred to as a reference node. However, other configurations ofaccess lines and/or reference lines are possible in accordance withvarious embodiments of the present disclosure.

The memory cell 105-a may include a logic storage component (e.g., amemory element, a storage element, a memory storage element), such as acapacitor 220 that has a first plate, cell plate 221, and a secondplate, cell bottom 222. The cell plate 221 and the cell bottom 222 maybe capacitively coupled through a dielectric material positioned betweenthem (e.g., in a DRAM application), or capacitively coupled through aferroelectric material positioned between them (e.g., in a FeRAMapplication). The cell plate 221 may be associated with a voltageV_(plate), and cell bottom 222 may be associated with a voltageV_(bottom), as illustrated in the circuit 200. The orientation of cellplate 221 and cell bottom 222 may be different (e.g., flipped) withoutchanging the operation of the memory cell 105-a. The cell plate 221 maybe accessed via the plate line 215 and cell bottom 222 may be accessedvia the digit line 210. As described herein, various logic states may bestored by charging, discharging, or polarizing the capacitor 220.

The capacitor 220 may be in electronic communication with the digit line210, and the stored logic state of the capacitor 220 may be read orsensed by operating various elements represented in circuit 200. Forexample, the memory cell 105-a may also include a cell selectioncomponent 230 which, in some examples, may be referred to as a switchingcomponent or a selector device coupled with an access line (e.g., thedigit line 210) and the capacitor 220. In some examples, a cellselection component 230 may be considered to be outside the illustrativeboundary of the memory cell 105-a, and the cell selection component 230may be referred to as a switching component or selector device coupledwith or between an access line (e.g., the digit line 210) and the memorycell 105-a.

The capacitor 220 may be selectively coupled with the digit line 210when the cell selection component 230 is activated (e.g., by way of anactivating logical signal), and the capacitor 220 can be selectivelyisolated from the digit line 210 when the cell selection component 230is deactivated (e.g., by way of a deactivating logical signal). Alogical signal or other selection signal or voltage may be applied to acontrol node 235 (e.g., a control node, a control terminal, a selectionnode, a selection terminal) of the cell selection component 230 (e.g.,via the word line 205). In other words, the cell selection component 230may be configured to selectively couple or decouple the capacitor 220and the digit line 210 based on a logical signal or voltage applied viathe word line 205 to the control node 235.

Activating the cell selection component 230 may be referred to asselecting the memory cell 105-a in some examples, and deactivating thecell selection component 230 may be referred to as deselecting thememory cell 105-a in some examples. In some examples, the cell selectioncomponent 230 is a transistor and its operation may be controlled byapplying an activation voltage to the transistor gate (e.g., a controlor selection node or terminal). The voltage for activating thetransistor (e.g., the voltage between the transistor gate terminal andthe transistor source terminal) may be a voltage greater than thethreshold voltage magnitude of the transistor. The word line 205 may beused to activate the cell selection component 230. For example, aselection voltage applied to the word line 205 (e.g., a word linelogical signal or a word line voltage) may be applied to the gate of atransistor of cell selection component 230, which may selectivelyconnect the capacitor 220 with the digit line 210 (e.g., providing aconductive path between the capacitor 220 and the digit line 210). Insome examples, activating the cell selection component 230 may bereferred to as selectively coupling the memory cell 105-a with the digitline 210.

In other examples, the positions of the cell selection component 230 andthe capacitor 220 in the memory cell 105-a may be switched, such thatcell selection component 230 may be coupled with or between the plateline 215 and the cell plate 221, and the capacitor 220 may be coupledwith or between the digit line 210 and the other terminal of the cellselection component 230. In such an embodiment, the cell selectioncomponent 230 may remain in electronic communication with the digit line210 through the capacitor 220. This configuration may be associated withalternative timing and biasing for access operations.

In examples that employ a ferroelectric capacitor 220, the capacitor 220may or may not fully discharge upon connection to the digit line 210. Invarious schemes, to sense the logic state stored by a ferroelectriccapacitor 220, a voltage may be applied to the plate line 215 and/or thedigit line 210, and the word line 205 may be biased (e.g., by activatingthe word line 205) to select the memory cell 105-a. In some cases, theplate line 215 and/or the digit line 210 may be virtually grounded andthen isolated from the virtual ground, which may be referred to as afloating condition, an idle condition, or a standby condition, prioractivating the word line 205.

Operation of the memory cell 105-a by varying the voltage to cell plate221 (e.g., via the plate line 215) may be referred to as “moving thecell plate.” Biasing the plate line 215 and/or the digit line 210 mayresult in a voltage difference (e.g., the voltage of the digit line 210minus the voltage of the plate line 215) across the capacitor 220. Thevoltage difference may accompany a change in the stored charge oncapacitor 220, where the magnitude of the change in stored charge maydepend on the initial state of the capacitor 220 (e.g., whether theinitial logic state stored a logic 1 or a logic 0). In some schemes, thechange in the stored charge of the capacitor 220 may cause a change inthe voltage of the digit line 210, which may be used by the sensecomponent 150-a to determine the stored logic state of the memory cell105-a.

The digit line 210 may be coupled with additional memory cells 105 (notshown), and the digit line 210 may have properties that result in anintrinsic capacitance 240 (e.g., on the order of picofarads (pF), whichmay in some cases be non-negligible), which may couple the digit line210 with a voltage source 250-a. The voltage source 250-a may representa common ground or virtual ground voltage, or the voltage of an adjacentaccess line of the circuit 200 (not shown). Although illustrated as aseparate element in FIG. 2, the intrinsic capacitance 240 may beassociated with properties distributed throughout the digit line 210.

In some examples, the intrinsic capacitance 240 may depend on physicalcharacteristics of the digit line 210, including conductor dimensions(e.g., length, width, thickness) of the digit line 210. The intrinsiccapacitance 240 may also depend on characteristics of adjacent accesslines or circuit components, proximity to such adjacent access lines orcircuit components, or insulation characteristics between the digit line210 and such access lines or circuit components. Thus, a change involtage of digit line 210 after selecting the memory cell 105-a maydepend on the net capacitance of (e.g., associated with) the digit line210. In other words, as charge flows along the digit line 210 (e.g., tothe digit line 210, from the digit line 210), some finite charge may bestored along the digit line 210 (e.g., in the intrinsic capacitance 240,other capacitance coupled with the digit line 210), and the resultingvoltage of the digit line 210 may depend on the net capacitance of thedigit line 210.

The resulting voltage of the digit line 210 after selecting the memorycell 105-a may be compared to a reference (e.g., a voltage of thereference line 265) by the sense component 150-a to determine the logicstate that was stored in the memory cell 105-a. In some examples, avoltage of the reference line 265 may be provided by a referencecomponent 285. In other examples, the reference component 285 may beomitted and a reference voltage may be provided, for example, byaccessing the memory cell 105-a to generate the reference voltage (e.g.,in a self-referencing access operation). Other operations may be used tosupport selecting and/or sensing the memory cell 105-a, includingoperations for supporting access schemes for activity-based dataprotection as described herein.

In some examples, the circuit 200 may include a signal developmentcomponent 280, which may be an example of a signal development circuitcoupled with or between the memory cell 105-a and the sense amplifier290. The signal development component 280 may amplify or otherwiseconvert signals of the digit line 210 prior to a sensing operation. Thesignal development component 280 may include, for example, a transistor,an amplifier, a cascode, or any other charge or voltage converter oramplifier component. In some examples, the signal development component280 may include a charge transfer sensing amplifier (CTSA). In someexamples with a signal development component 280, a line between thesense amplifier 290 and the signal development component 280 may bereferred to as a signal line (e.g., signal line 260). In some examples(e.g., examples with or without a signal development component 280), thedigit line 210 may connect directly with the sense amplifier 290.

In some examples, the circuit 200 may include a bypass line 270 that maypermit selectively bypassing the signal development component 280 orsome other signal generation circuit between the memory cell 105-a andthe sense amplifier 290. In some examples, the bypass line 270 may beselectively enabled by way of a switching component 275. In other words,when the switching component 275 is activated, the digit line 210 may becoupled with the signal line 260 via the bypass line 270 (e.g., couplingthe memory cell 105-a with the sense component 150-a).

In some examples, when the switching component 275 is activated, thesignal development component 280 may be selectively isolated from one orboth of the digit line 210 or the signal line 260 (e.g., by anotherswitching component or selection component, not shown). When theswitching component 275 is deactivated, the digit line 210 may beselectively coupled with the signal line 260 via the signal developmentcomponent 280. In other examples, a selection component may be used toselectively couple the memory cell 105-a (e.g., the digit line 210) withone of the signal development component 280 or the bypass line 270.Additionally or alternatively, in some examples, a selection componentmay be used to selectively couple the sense amplifier 290 with one ofthe signal development component 280 or the bypass line 270. In someexamples, a selectable bypass line 270 may support generating a sensesignal for detecting a logic state of the memory cell 105-a by using thesignal development component 280, and generating a write signal to writea logic state to the memory cell 105-a that bypasses the signaldevelopment component 280.

Some examples of a memory device that supports the described accessschemes for activity-based data protection may share a common accessline (not shown) between a memory cell 105 and a sense amplifier 290 tosupport generating a sense signal and a reference signal from the samememory cell 105. In one example, a common access line between a signaldevelopment component 280 and a sense amplifier 290 may be referred toas a “common line,” an “AMPCAP line,” or an “AMPCAP node,” and thecommon access line may take the place of the signal line 260 and thereference line 265 illustrated in circuit 200. In such examples thecommon access line may be connected to the sense amplifier 290 at twodifferent nodes (e.g., a first node 291 and a second node 292, asdescribed herein). In some examples, a common access line may permit aself-referencing read operation to share, in both a signal generatingoperation and a reference generating operation, components that mayexist between the sense amplifier 290 and a memory cell 105 beingaccessed. Such a configuration may reduce the sensitivity of the senseamplifier 290 to operational variations of various components in amemory device, such as memory cells 105, access lines (e.g., a word line205, a digit line 210, a plate line 215), signal development circuits(e.g., signal development component 280), transistors, voltage sources250, and others.

Although the digit line 210 and the signal line 260 are identified asseparate lines, the digit line 210, the signal line 260, and any otherlines connecting a memory cell 105 with a sense component 150 may bereferred to as a single access line in accordance with the presentdisclosure. Constituent portions of such an access line may beidentified separately for the purposes of illustrating interveningcomponents and intervening signals in various example configurations.

The sense amplifier 290 may include various transistors or amplifiers todetect, convert, or amplify a difference in signals, which may bereferred to as latching. For example, the sense amplifier 290 mayinclude circuit elements that receive and compare a sense signal voltage(e.g., V_(sig)) at the first node 291 with a reference signal voltage(e.g., V_(ref)) at the second node 292. An output of the sense amplifiermay be driven to a higher (e.g., a positive) or a lower voltage (e.g., anegative voltage, a ground voltage) based on the comparison at the senseamplifier 290.

For example, if the first node 291 has a lower voltage than the secondnode 292, the output of the sense amplifier 290 may be driven to arelatively lower voltage of a first sense amplifier voltage source 250-b(e.g., a voltage of V_(L), which may be a ground voltage substantiallyequal to V₀ or a negative voltage). A sense component 150 that includesthe sense amplifier 290 may latch the output of the sense amplifier 290to determine the logic state stored in the memory cell 105-a (e.g.,detecting a logic 0 when the first node 291 has a lower voltage than thesecond node 292).

If the first node 291 has a higher voltage than the second node 292, theoutput of the sense amplifier 290 may be driven to the voltage of asecond sense amplifier voltage source 250-c (e.g., a voltage of V_(H)).A sense component 150 that includes the sense amplifier 290 may latchthe output of the sense amplifier 290 to determine the logic statestored in the memory cell 105-a (e.g., detecting a logic 1 when thefirst node 291 has a higher voltage than the second node 292). Thelatched output of the sense amplifier 290, corresponding to the detectedlogic state of memory cell 105-a, may then be output via one or moreinput/output (I/O) lines (e.g., I/O line 295), which may include anoutput through a column component 135 via input/output component 160described with reference to FIG. 1.

To perform a write operation on the memory cell 105-a, a voltage may beapplied across the capacitor 220. Various methods may be used. In oneexample, the cell selection component 230 may be activated through theword line 205 (e.g., by activating the word line 205) to electricallyconnect the capacitor 220 to the digit line 210. A voltage may beapplied across capacitor 220 by controlling the voltage of the cellplate 221 (e.g., through the plate line 215) and the cell bottom 222(e.g., through the digit line 210).

For example, to write a logic 0, the cell plate 221 may be taken high(e.g., applying a positive voltage to the plate line 215), and the cellbottom 222 may be taken low (e.g., grounding the digit line 210,virtually grounding the digit line 210, applying a negative voltage tothe digit line 210). The opposite process may be performed to write alogic 1, where the cell plate 221 is taken low and the cell bottom 222is taken high. In some cases, the voltage applied across the capacitor220 during a write operation may have a magnitude equal to or greaterthan a saturation voltage of a ferroelectric material in the capacitor220, such that the capacitor 220 is polarized, and thus maintains acharge even when the magnitude of applied voltage is reduced, or if azero net voltage is applied across the capacitor 220. In some examples,the sense amplifier 290 may be used to perform the write operations,which may include coupling the first sense amplifier voltage source250-b or the second sense component voltage source 250-c with the digitline. When the sense amplifier 290 is used to perform the writeoperations, the signal development component 280 may or may not bebypassed (e.g., by applying a write signal via the bypass line 270).

The circuit 200, including the sense amplifier 290, the cell selectioncomponent 230, the signal development component 280, or the referencecomponent 285, may include various types of transistors. For example,the circuit 200 may include n-type transistors, where applying arelative positive voltage to the gate of the n-type transistor that isabove a threshold voltage for the n-type transistor (e.g., an appliedvoltage having a positive magnitude, relative to a source terminal, thatis greater than a threshold voltage) enables a conductive path betweenthe other terminals of the n-type transistor (e.g., the source terminaland a drain terminal).

In some examples, the n-type transistor may act as a switchingcomponent, where the applied voltage is a logical signal that is used toenable conductivity through the transistor by applying a relatively highlogical signal voltage (e.g., a voltage corresponding to a logic 1state, which may be associated with a positive logical signal voltagesupply), or to disable conductivity through the transistor by applying arelatively low logical signal voltage (e.g., a voltage corresponding toa logic 0 state, which may be associated with a ground or virtual groundvoltage). In some examples where a n-type transistor is employed as aswitching component, the voltage of a logical signal applied to the gateterminal may be selected to operate the transistor at a particularworking point (e.g., in a saturation region or in an active region).

In some examples, the behavior of a n-type transistor may be morecomplex than a logical switching, and selective conductivity across thetransistor may also be a function of varying source and drain voltages.For example, the applied voltage at the gate terminal may have aparticular voltage level (e.g., a clamping voltage) that is used toenable conductivity between the source terminal and the drain terminalwhen the source terminal voltage is below a certain level (e.g., belowthe gate terminal voltage minus the threshold voltage). When the voltageof the source terminal voltage or drain terminal voltage rises above thecertain level, the n-type transistor may be deactivated such that theconductive path between the source terminal and drain terminal isopened.

Additionally or alternatively, the circuit 200 may include p-typetransistors, where applying a relative negative voltage to the gate ofthe p-type transistor that is above a threshold voltage for the p-typetransistor (e.g., an applied voltage having a negative magnitude,relative to a source terminal, that is greater than a threshold voltage)enables a conductive path between the other terminals of the p-typetransistor (e.g., the source terminal and a drain terminal).

In some examples, the p-type transistor may act as a switchingcomponent, where the applied voltage is a logical signal that is used toenable conductivity by applying a relatively low logical signal voltage(e.g., a voltage corresponding to a logical “1” state, which may beassociated with a negative logical signal voltage supply), or to disableconductivity by applying a relatively high logical signal voltage (e.g.,a voltage corresponding to a logical “0” state, which may be associatedwith a ground or virtual ground voltage). In some examples where ap-type transistor is employed as a switching component, the voltage of alogical signal applied to the gate terminal may be selected to operatethe transistor at a particular working point (e.g., in a saturationregion or in an active region).

In some examples, the behavior of a p-type transistor may be morecomplex than a logical switching by the gate voltage, and selectiveconductivity across the transistor may also be a function of varyingsource and drain voltages. For example, the applied voltage at the gateterminal may have a particular voltage level that is used to enableconductivity between the source terminal and the drain terminal so longas the source terminal voltage is above a certain level (e.g., above thegate terminal voltage plus the threshold voltage). When the voltage ofthe source terminal voltage falls below the certain level, the p-typetransistor may be deactivated such that the conductive path between thesource terminal and drain terminal is opened.

A transistor of the circuit 200 may be a field-effect transistor (FET),including a metal oxide semiconductor FET, which may be referred to as aMOSFET. These, and other types of transistors may be formed by dopedregions of material on a substrate. In some examples, the transistor(s)may be formed on a substrate that is dedicated to a particular componentof the circuit 200 (e.g., a substrate for the sense amplifier 290, asubstrate for the signal development component 280, a substrate for thememory cell 105-a), or the transistor(s) may be formed on a substratethat is common for particular components of the circuit 200 (e.g., asubstrate that is common for the sense amplifier 290, the signaldevelopment component 280, and the memory cell 105-a). Some FETs mayhave a metal portion including aluminum or other metal, but some FETsmay implement other non-metal materials such as polycrystalline silicon,including those FETs that may be referred to as a MOSFET. Further,although an oxide portion may be used as a dielectric portion of a FET,other non-oxide materials may be used in a dielectric material in a FET,including those FETs that may be referred to as a MOSFET.

In some examples in accordance with the present disclosure, an accessoperation may be performed on a selected memory cell 105 other than thememory cell 105-a that is coupled with the digit line 210. In such anexample, the memory cell 105-a may be referred to as a non-selectedmemory cell. The access operation may be associated with biasing thedigit line 210 and the plate line 215. Although the cell selectioncomponent 230 of the non-selected memory cell 105-a may be deactivated,leakage charge may flow through the cell selection component 230 (e.g.,via the digit line 210). Such a leakage charge may accumulate on thenon-selected memory cell 105-a (e.g., at an intermediate node of thememory cell 105-a, at the cell bottom 222 of the capacitor 220), or flowfrom the non-selected memory cell 105-a, or may cause a bias (e.g., anon-zero voltage) to accumulate across at least some of the non-selectedmemory cell 105-a which, in some examples, may cause a loss of datastored in at least some of the non-selected memory cells 105.

In accordance with examples of the present disclosure, operations may beperformed on a memory section 110 that includes the memory cell 105-a toencourage or otherwise support the dissipation of accumulated leakagecharge or bias from the non-selected memory cell 105-a, and other memorycells 105 of the memory section 110 that may have accumulated leakagecharge or bias. For example, according to a periodic interval (e.g., aperiodic section selection interval, a periodic dissipation interval, aperiodic equalization interval, a periodic voltage adjustment interval),a memory controller 170 may select the memory section 110 that includesthe memory cell 105-a for a voltage adjustment operation (e.g., when thememory section 110 that includes the memory cell 105-a is amost-frequently accessed memory section 110 of a memory device 100 or amost-frequently accessed memory section 110 of a memory bank of a memorydevice 100), and as part of the voltage adjustment operation the cellselection component 230 may be activated (e.g., by activating the wordline 205). While the cell selection component 230 is activated, thedigit line 210 and the plate line 215 may be coupled with voltagesources that support the dissipation of accumulated leakage charge orbias. For example, the digit line 210 and the plate line 215 may becoupled with a same voltage source, or coupled with voltage sourceshaving the same voltage, or coupled with voltage sources having voltagesthat otherwise support the dissipation of leakage charge or biasaccumulated at non-selected memory cell 105-a.

In some examples, the described operations associated with such adissipation of leakage charge or bias may be referred to as a voltageadjustment operation. By performing the operations described herein,leakage charge or bias accumulated at memory cells 105 of amost-frequently accessed memory section 110 may be dissipated, which maymitigate or prevent the accumulation of leakage charge or bias acrosssuccessive access operations of the memory section 110 and improve theability of the memory device 100 to maintain stored data. Further, byselecting a most-frequently accessed memory section 110 (e.g., of amemory device 100, of a bank of a set of banks of a memory device 100)for such operations according to a periodic interval, a memory devicemay operate in a more-targeted manner than when such operations areperformed, for example, without considering a frequency of accessoperations on respective memory sections 110.

FIG. 3 illustrates an example of non-linear electrical properties withhysteresis plots 300-a and 300-b for a memory cell 105 that supportsaccess schemes for activity-based data protection in a memory device inaccordance with various embodiments of the present disclosure. Thehysteresis plots 300-a and 300-b may illustrate an example writingprocess and reading process, respectively, for a memory cell 105employing a ferroelectric capacitor 220 as described with reference toFIG. 2. The hysteresis plots 300-a and 300-b depict the charge, Q,stored on the ferroelectric capacitor 220 as a function of a voltagedifference V_(cap), between the terminals of the ferroelectric capacitor220 (e.g., when charge is permitted to flow into or out of theferroelectric capacitor 220 according to the voltage differenceV_(cap)). For example, the voltage difference V_(cap) may represent thedifference in voltage between a digit line side of the capacitor 220 anda plate line side of the capacitor 220 (e.g., V_(bottom)−V_(plate)).

A ferroelectric material is characterized by a spontaneous electricpolarization, where the material may maintain a non-zero electric chargein the absence of an electric field. Examples of ferroelectric materialsinclude barium titanate (BaTiO₃), lead titanate (PbTiO₃), lead zirconiumtitanate (PZT), and strontium bismuth tantalate (SBT). Ferroelectriccapacitors 220 described herein may include these or other ferroelectricmaterials. Electric polarization within a ferroelectric capacitor 220results in a net charge at the surface of the ferroelectric material,and attracts opposite charge through the terminals of the ferroelectriccapacitor 220. Thus, charge is stored at the interface of theferroelectric material and the capacitor terminals. Because the electricpolarization may be maintained in the absence of an externally appliedelectric field for relatively long times, even indefinitely, chargeleakage may be significantly decreased as compared with, for example,capacitors without ferroelectric properties such as those used inconventional DRAM arrays. Employing ferroelectric materials may reducethe need to perform refresh operations as described above for some DRAMarchitectures, such that maintaining logic states of an FeRAMarchitecture may be associated with substantially lower powerconsumption than maintaining logic states of a DRAM architecture.

The hysteresis plots 300-a and 300-b may be understood from theperspective of a single terminal of a ferroelectric capacitor 220. Byway of example, if the ferroelectric material has a negativepolarization, positive charge accumulates at the associated terminal ofthe ferroelectric capacitor 220. If the ferroelectric material has apositive polarization, a negative charge accumulates at the associatedterminal of the ferroelectric capacitor 220.

Additionally, it should be understood that the voltages in thehysteresis plots 300-a and 300-b represent a voltage difference acrossthe capacitor (e.g., an electric potential between the terminals of theferroelectric capacitor 220) and are directional. For example, apositive voltage may be realized by applying a positive voltage to theperspective terminal (e.g., a cell bottom 222) and maintaining thereference terminal (e.g., a cell plate 221) at ground or virtual ground(or approximately zero volts (0V)). In some examples, a negative voltagemay be applied by maintaining the perspective terminal at ground andapplying a positive voltage to the reference terminal (e.g., cell plate221). In other words, positive voltages may be applied to arrive at anegative voltage difference V_(cap) across the ferroelectric capacitor220 and thereby negatively polarize the terminal in question. Similarly,two positive voltages, two negative voltages, or any combination ofpositive and negative voltages may be applied to the appropriatecapacitor terminals to generate the voltage difference V_(cap) shown inthe hysteresis plots 300-a and 300-b.

As depicted in the hysteresis plot 300-a, a ferroelectric material usedin a ferroelectric capacitor 220 may maintain a positive or negativepolarization when there is no net voltage difference between theterminals of the ferroelectric capacitor 220. For example, thehysteresis plot 300-a illustrates two possible polarization states, acharge state 305-a and a charge state 310-b, which may represent apositively saturated polarization state and a negatively saturatedpolarization state, respectively. The charge states 305-a and 310-a maybe at a physical condition illustrating remnant polarization (Pr)values, which may refer to the polarization (or charge) that remainsupon removing the external bias (e.g., voltage). The coercive voltage isthe voltage at which the charge or polarization is zero. According tothe example of the hysteresis plot 300-a, the charge state 305-a mayrepresent a logic 1 when no voltage difference is applied across theferroelectric capacitor 220, and the charge state 310-a may represent alogic 0 when no voltage difference is applied across the ferroelectriccapacitor 220. In some examples, the logic values of the respectivecharge states may be reversed to accommodate other schemes for operatinga memory cell 105.

A logic 0 or 1 may be written to the memory cell by controlling theelectric polarization of the ferroelectric material, and thus the chargeon the capacitor terminals, by applying a net voltage difference acrossthe ferroelectric capacitor 220. For example, the voltage 315 may be avoltage equal to or greater than a positive saturation voltage, andapplying the voltage 315 across the ferroelectric capacitor 220 mayresult in charge accumulation until the charge state 305-b is reached(e.g., writing a logic 1). Upon removing the voltage 315 from theferroelectric capacitor 220 (e.g., applying a zero net voltage acrossthe terminals of the ferroelectric capacitor 220), the charge state ofthe ferroelectric capacitor 220 may follow the path 320 shown betweenthe charge state 305-b and the charge state 305-a at zero voltage acrossthe capacitor. In other words, charge state 305-a may represent a logic1 state at an equalized voltage across a ferroelectric capacitor 220that has been positively saturated.

Similarly, voltage 325 may be a voltage equal to or lesser than anegative saturation voltage, and applying the voltage 325 across theferroelectric capacitor 220 may result in charge accumulation until thecharge state 310-b is reached (e.g., writing a logic 0). Upon removingthe voltage 325 from the ferroelectric capacitor 220 (e.g., applying azero net voltage across the terminals of the ferroelectric capacitor220), the charge state of the ferroelectric capacitor 220 may follow thepath 330 shown between the charge state 310-b and the charge state 310-aat zero voltage across the capacitor. In other words, charge state 310-amay represent a logic 0 state at an equalized voltage across aferroelectric capacitor 220 that has been negatively saturated. In someexamples, the voltage 315 and the voltage 325, representing saturationvoltages, may have the same magnitude, but opposite polarity across theferroelectric capacitor 220.

To read, or sense, the stored state of a ferroelectric capacitor 220, avoltage may also be applied across the ferroelectric capacitor 220. Inresponse to the applied voltage, the subsequent charge Q stored by theferroelectric capacitor changes, and the degree of the change may dependon the initial polarization state, the applied voltages, intrinsic orother capacitance on access lines, and other factors. In other words,the charge state resulting from a read operation may depend on whetherthe charge state 305-a, or the charge state 310-a, or some other chargestate was initially stored, among other factors.

The hysteresis plot 300-b illustrates an example of access operationsfor reading stored charge states 305-a and 310-a. A read voltage 335 maybe applied, for example, as a voltage difference via a digit line 210and a plate line 215 as described with reference to FIG. 2. Thehysteresis plot 300-b may illustrate read operations where the readvoltage 335 is negative voltage difference V_(cap) (e.g., whereV_(bottom)−V_(plate) is negative). A negative read voltage across theferroelectric capacitor 220 may be referred to as a “plate high” readoperation, where a plate line 215 is taken initially to a high voltage,and a digit line 210 is initially at a low voltage (e.g., a groundvoltage). Although the read voltage 335 is shown as a negative voltageacross the ferroelectric capacitor 220, in alternative access operationsa read voltage may be a positive voltage across the ferroelectriccapacitor 220, which may be referred to as a “plate low” read operation.

The read voltage 335 may be applied across the ferroelectric capacitor220 when a memory cell 105 is selected (e.g., by activating a cellselection component 230 via a word line 205 as described with referenceto FIG. 2). Upon applying the read voltage 335 to the ferroelectriccapacitor 220, charge may flow into or out of the ferroelectriccapacitor 220 via the associated digit line 210 and plate line 215, anddifferent charge states may result depending on whether theferroelectric capacitor 220 was at the charge state 305-a (e.g., alogic 1) or at the charge state 310-a (e.g., a logic 0), or some othercharge state.

When performing a read operation on a ferroelectric capacitor 220 at thecharge state 310-a (e.g., a logic 0), additional negative charge mayaccumulate across the ferroelectric capacitor 220, and the charge statemay follow path 340 until reaching the charge and voltage of the chargestate 310-c. The amount of charge flowing through the capacitor 220 maybe related to the intrinsic or other capacitance of the digit line 210(e.g., intrinsic capacitance 240 described with reference to FIG. 2).

Accordingly, as shown by the transition between the charge state 310-aand the charge state 310-c, the resulting voltage 350 across theferroelectric capacitor 220 may be a relatively large negative value dueto the relatively large change in voltage for the given change incharge. Thus, upon reading a logic 0 in a “plate high” read operation,the digit line plate, 5 voltage, equal to the sum of V_(PL) and thevalue of (V_(bottom)−V_(plate)) at the charge state 310-c, may be arelatively low voltage. Such a read operation may not change the remnantpolarization of the ferroelectric capacitor 220 that stored the chargestate 310-a, and thus after performing the read operation theferroelectric capacitor 220 may return to the charge state 310-a viapath 340 when the read voltage 335 is removed (e.g., by applying a zeronet voltage across the ferroelectric capacitor 220, by equalizing thevoltage across the ferroelectric capacitor 220). Thus, performing a readoperation with a negative read voltage on a ferroelectric capacitor 220with a charge state 310-a may be considered a non-destructive readprocess.

When performing the read operation on the ferroelectric capacitor 220 atthe charge state 305-a (e.g., a logic 1), the stored charge may reversepolarity as a net negative charge accumulates across the ferroelectriccapacitor 220, and the charge state may follow the path 360 untilreaching the charge and voltage of the charge state 305-c. The amount ofcharge flowing through the ferroelectric capacitor 220 may again berelated to the intrinsic or other capacitance of the digit line 210(e.g., intrinsic capacitance 240 described with reference to FIG. 2).Accordingly, as shown by the transition between the charge state 305-aand the charge state 305-c, the resulting voltage 355 may, in somecases, be a relatively small negative value due to the relatively smallchange in voltage for the given change in charge. Thus, upon reading alogic 1 in a “plate high” read operation, the digit line voltage, equalto the sum of V_(PL) and the value of (V_(bottom)−V_(plate)) at thecharge state 305-c, may be a relatively plate, high voltage.

In some examples, a read operation with a negative read voltage (e.g.,read voltage 335) may result in a reduction or a reversal of remnantpolarization of the capacitor 220 that stored the charge state 305-a. Inother words, according to the properties of the ferroelectric material,after performing the read operation the ferroelectric capacitor 220 maynot return to the charge state 305-a when the read voltage 335 isremoved (e.g., by applying a zero net voltage across the ferroelectriccapacitor 220, by equalizing the voltage across the ferroelectriccapacitor 220). Rather, when applying a zero net voltage across theferroelectric capacitor 220 after a read operation with read voltage335, the charge state may follow path 365 from the charge state 305-c tothe charge state 305-d, illustrating a net reduction in polarizationmagnitude (e.g., a less positively polarized charge state than initialcharge state 305-a, illustrated by the difference in charge between thecharge state 305-a and the charge state 305-d). Thus, performing a readoperation with a negative read voltage on a ferroelectric capacitor 220with a charge state 305-a may be described as a destructive readprocess. However, in some sensing schemes, a reduced remnantpolarization may still be read as the same stored logic state as asaturated remnant polarization state (e.g., supporting detection of alogic 1 from both the charge state 305-a and the charge state 305-d),thereby providing a degree of non-volatility for a memory cell 105 withrespect to read operations.

The transition from the charge state 305-a to the charge state 305-d maybe illustrative of a sensing operation that is associated with a partialreduction and/or partial reversal in polarization of a ferroelectriccapacitor 220 of a memory cell 105 (e.g., a reduction in the magnitudeof charge Q from the charge state 305-a to the charge state 305-d). Insome examples, the amount of change in polarization of a ferroelectriccapacitor 220 of a memory cell 105 as a result of a sensing operationmay be selected according to a particular sensing scheme. In someexamples, sensing operations having a greater change in polarization ofa ferroelectric capacitor 220 of a memory cell 105 may be associatedwith relatively greater robustness in detecting a logic state of amemory cell 105. In some sensing schemes, sensing a logic 0 of aferroelectric capacitor 220 at the charge state 305-a may result in afull reversal of polarization, with the ferroelectric capacitor 220transitioning from the charge state 305-a to the charge state 310-aafter the sensing operation.

The position of the charge state 305-c and the charge state 310-c afterinitiating a read operation may depend on a number of factors, includingthe specific sensing scheme and circuitry. In some cases, the finalcharge may depend on the net capacitance of the digit line 210 coupledwith the memory cell 105, which may include an intrinsic capacitance240, integrator capacitors, and others. For example, if a ferroelectriccapacitor 220 is electrically coupled with digit line 210 at 0V and theread voltage 335 is applied to the plate line, the voltage of the digitline 210 may rise when the memory cell 105 is selected due to chargeflowing from the ferroelectric capacitor 220 to the net capacitance ofthe digit line 210. Thus, a voltage measured at a sense component 150may not be equal to the read voltage 335, or the resulting voltages 350or 355, and instead may depend on the voltage of the digit line 210following a period of charge sharing.

The position of the charge state 305-c and the charge state 310-c onhysteresis plot 300-b upon initiating a read operation may depend on thenet capacitance of the digit line 210 and may be determined through aload-line analysis. In other words, the charge states 305-c and 310-cmay be defined with respect to the net capacitance of the digit line210. As a result, the voltage of the ferroelectric capacitor 220 afterinitiating a read operation (e.g., voltage 350 when reading theferroelectric capacitor 220 that stored the charge state 310-a, voltage355 when reading the ferroelectric capacitor 220 that stored the chargestate 305-a), may be different and may depend on the initial state ofthe ferroelectric capacitor 220.

The initial state (e.g., charge state, logic state) of the ferroelectriccapacitor 220 may be determined by comparing the voltage of a digit line210 (or signal line 260, where applicable) resulting from the readoperation with a reference voltage (e.g., via a reference line 265 asdescribed with reference to FIG. 2, or via a common access line). Insome examples, the digit line voltage may be the sum of the plate linevoltage and the final voltage across the ferroelectric capacitor 220(e.g., voltage 350 when reading the ferroelectric capacitor 220 having astored the charge state 310-a, or voltage 355 when reading theferroelectric capacitor 220 having a stored the charge state 305-a). Insome examples, the digit line voltage may be the difference between theread voltage 335 and the final voltage across the capacitor 220 (e.g.,(read voltage 335-voltage 350) when reading the ferroelectric capacitor220 having a stored the charge state 310-a, (read voltage 335-voltage355) when reading the ferroelectric capacitor 220 having a stored thecharge state 305-a).

In some sensing schemes, a reference voltage may be generated such thatthe reference voltage is between the possible voltages that may resultfrom reading different logic states. For example, a reference voltagemay be selected to be lower than the resulting digit line voltage whenreading a logic 1, and higher than the resulting digit line voltage whenreading a logic 0. In other examples, a comparison may be made at aportion of a sense component 150 that is different from a portion wherea digit line is coupled, and therefore a reference voltage may beselected to be lower than the resulting voltage at the comparisonportion of the sense component 150 when reading a logic 1, and higherthan the resulting voltage at the comparison portion of the sensecomponent 150 when reading a logic 0. During comparison by the sensecomponent 150, the voltage based on the sensing may be determined to behigher or lower than the reference voltage, and the stored logic stateof the memory cell 105 (e.g., a logic 0, a logic 1) may thus bedetermined.

During a sensing operation, the resulting signals from reading variousmemory cells 105 may be a function of manufacturing or operationalvariations between the various memory cells 105. For example, capacitors220 of various memory cells 105 may have different levels of capacitanceor saturation polarization, so that a logic 1 may be associated withdifferent levels of charge from one memory cell to the next, and a logic0 may be associated with different levels of charge from one memory cellto the next. Further, intrinsic or other capacitance (e.g., intrinsiccapacitance 240 described with reference to FIG. 2) may vary from onedigit line 210 to the next digit line 210 in a memory device, and mayalso vary within a digit line 210 from the perspective of one memorycell 105 to the next memory cell 105 on the same digit line. Thus, forthese and other reasons, reading a logic 1 may be associated withdifferent levels of digit line voltage from one memory cell to the next(e.g., resulting voltage 350 may vary from reading one memory cell 105to the next), and reading a logic 0 may be associated with differentlevels of digit line voltage from one memory cell to the next (e.g.,resulting voltage 355 may vary from reading one memory cell 105 to thenext).

In some examples, a reference voltage may be provided between astatistical average of voltages associated with reading a logic 1 and astatistical average of voltages associated with reading a logic 0, butthe reference voltage may be relatively closer to the resulting voltageof reading one of the logic states for any given memory cell 105. Theminimum difference between a resulting voltage of reading a particularlogic state (e.g., as a statistical value for reading a plurality ofmemory cells 105 of a memory device) and an associated level of areference voltage may be referred to as a “minimum read voltagedifference,” and having a low minimum read voltage difference may beassociated with difficulties in reliably sensing the logic states ofmemory cells in a given memory device.

In some examples, a sense component 150 may be designed to employself-referencing techniques, where a memory cell 105 itself is involvedin providing a reference signal when reading the memory cell 105.However, when using the same memory cell 105 for providing both a sensesignal and a reference signal, the sense signal and the reference signalmay be substantially identical when performing access operations that donot change a state stored by the memory cell 105. For example, whenperforming a self-referencing read operation on a memory cell 105storing a logic 1 (e.g., storing a charge state 310-a), a first accessoperation that may include applying the read voltage 335 may follow path340, and a second operation that may also include applying the readvoltage 335 may also follow path 340, and the first and second accessoperations may result in substantially the same access signals (e.g.,from the perspective of the memory cell 105). In such cases, whenemploying a sense component 150 that relies on a difference between asense signal and a reference signal to detect a logic state stored bythe memory cell 105, some other portion of a memory device may providesuch a difference in the event that access operations might providesubstantially equal sense and reference signals.

In some examples in accordance with the present disclosure, cellselection components 230 of non-selected memory cells 105 of a memorysection 110 may be deactivated, but leakage charge may nonetheless flowthrough the deactivated cell selection components 230 of the memorysection 110 during an access operation associated with a different,selected memory cell 105 of the memory section 110. In an example of aferroelectric memory cell 105, the leakage charge or bias may accumulateat a ferroelectric capacitor 220 (e.g., a cell bottom 222) ofnon-selected memory cells 105 of the memory section 110, which may alterthe polarization of the ferroelectric capacitor 220.

For example, when the ferroelectric capacitor 220 of a non-selectedmemory cell 105 of a memory section 110 is at a charge state 305-a(e.g., storing a logic 1), leakage charge associated with an accessoperation on a selected memory cell 105 (e.g., a plate high readoperation for a selected memory cell 105, a write operation associatedwith writing a logic 0 on a selected memory cell 105) of the memorysection may cause the charge state of the non-selected memory cell 105to follow at least a portion of the path 360. In some examples, a firstaccess operation on a selected memory cell 105 may cause theferroelectric capacitor 220 of a non-selected memory cell to reach thecharge state 305-e (e.g., accumulating leakage charge illustrated by thechange in charge Q from charge state 305-a to charge state 305-e,accumulating a bias illustrated by the change in voltage V_(cap) fromcharge state 305-a to charge state 305-e). However, in the event thatthe non-selected memory cell 105 remains as non-selected for subsequentaccess operations for selected memory cells 105 (e.g., a same selectedmemory cell 105, one or more different selected memory cells 105) of thesame memory section 110, the non-selected memory cell 105 may continuealong the path 360 as leakage charge or bias continues to accumulate,until reaching charge state 305-c, for example.

The charge state 305-c may represent a substantial loss of polarization,which may be represented by the difference in stored charge between thecharge state 305-a and the charge state 305-d. In other words, if thevoltage across the non-selected memory cell 105 is equalized after a setof access operations for selected memory cells other than thenon-selected memory cell 105, the non-selected memory cell 105 mayfollow the path 365 from the charge state 305-c to the charge state305-d, illustrating a substantially lower polarization or charge thanthe charge state 305-a. In some examples, this loss of charge orpolarization may be associated with a charge state that is indeterminateregarding one logic state or another. In some examples, a charge statemay become indeterminate if a polarization has decreased more than 30%from a saturated polarization state (e.g., less than 70% of the charge Qassociated with the charge state 305-a). Thus, in some examples, thetransition between charge state 305-a and charge state 305-d (e.g., viacharge state 305-c) as a result of an accumulation of leakage charge orbias may represent a loss of data from such leakage charge.

In accordance with examples of the present disclosure, operations may beperformed on a memory section 110 to encourage or otherwise support thedissipation of leakage charge or bias from memory cells 105 of thememory section 110, which may reduce or eliminate data loss that mayotherwise result from an accumulation of leakage charge or bias. Forexample, after access operations on selected memory cells 105 of amemory section 110, the charge state of non-selected memory cells 105may follow at least a portion of the path 360 as a result of leakagecharge caused by the access operations. A memory controller 170 mayselect a memory section 110 for a voltage adjustment operation based atleast in part on a determined access history of a set of memory sections110 of a memory device (e.g., selecting a memory section 110 having ahighest quantity of access operations performed since a prior voltageadjustment operation (e.g., equalization operation, dissipationoperation) on the respective memory section 110, a memory section havinga highest quantity of access operations performed since a memory device100 was powered on). As part of the voltage adjustment operation, cellselection components 230 of each of the memory cells 105 of the memorysection 110 may be activated (e.g., by activating each of the word lines205 associated with the memory section 110).

While the cell selection components 230 are activated, associated digitlines 210 and plate lines 215 of the memory section 110 may be coupledwith voltage sources that support the dissipation of accumulated leakagecharge or bias. For example, the associated digit lines 210 and platelines 215 of the memory section 110 may be coupled with a same voltagesource, or coupled with voltage sources having the same voltage (e.g., aground voltage, a zero voltage, a non-zero voltage), or coupled withvoltage sources having voltages that otherwise support the dissipationof leakage charge or bias accumulated at memory cells 105 of the memorysection 110. In other words, in some examples, a zero voltage orequalized voltage may be applied across the memory cells 105, which maycause memory cells 105 to transition from a charge state 305 associatedwith a non-zero bias (e.g., charge state 305-e) to a charge state 305with a zero bias (e.g., charge state 305-f), which may be referred to asa zero capacitor voltage V_(cap).

In some examples, the selection of memory sections 110 for the describedvoltage adjustment operations may be performed according to an interval(e.g., a periodic section selection interval, a periodic voltageadjustment interval, a periodic dissipation interval, a periodicequalization interval), where such an interval corresponds to a quantityof access operations or a period of time that is associated with arelatively small loss of polarization (e.g., the difference in storedcharge between the charge state 305-a and the charge state 305-f) innon-selected memory cells 105 of a memory section 110. In some examples,the relatively small loss of charge or polarization may be associatedwith charge states that remain determinate as to whether the associatedmemory cells store one logic state or another. In other words, in someexamples, a logic 1 may be detected for a ferroelectric capacitor 220 atthe charge state 305-a or 305-f Thus, in some examples, the transitionbetween charge state 305-a and charge state 305-f as a result of anaccumulation of leakage charge or bias from access operations mayrepresent data being maintained despite such leakage charge or bias. Insome examples, a charge state may be determinate (e.g., may stillrepresent a state that is detectible for a particular logic state) solong as the polarization is within 30% of a saturated polarizationstate.

In some examples, subsequent access operations may be performed in whichnon-selected memory cells 105 of a memory section 110 store the chargestate 305-f In such examples, the non-selected memory cells 105 of thememory section 110 may alternate between the charge states 305-f and305-e as a result of a subsequent access operations on the memorysection 110, and a subsequent equalization, discharge operation, orvoltage adjustment operation, respectively. Accordingly, by performingthe activity-based voltage adjustment operations described herein,leakage charge or bias accumulated at memory cells 105 of a memorysection 110 may be dissipated after various access operation on thememory section 110. Such dissipation or equalization may mitigate orprevent the accumulation of leakage charge or bias across successiveaccess operations and improve the ability of the memory device 100 tomaintain stored data. Further, by selecting a particular memory section110 for such operations according to a periodic interval, a memorydevice 100 may operate more efficiently than when such operations areperformed, for example, after each access operation.

FIG. 4 illustrates an example of a circuit 400 of a memory device thatsupports access schemes for activity-based data protection in a memorydevice in accordance with various embodiments of the present disclosure.Components of the circuit 400 may be examples of the correspondingcomponents described with reference to FIGS. 1 through 3.

The circuit 400 may include a first memory section 110-b including afirst set of memory cells 105-b (e.g., memory cells 105-b-11 through105-b-mn), which may be illustrative of an array of memory cells 105having m columns and n rows. Each of the memory cells 105-b may becoupled with a word line 205-a of the first memory section 110-b (e.g.,one of word lines 205-a-1 through 205-a-n), a digit line 210-a of thefirst memory section 110-b (e.g., one of digit lines 210-a-1 through210-a-m), and a plate line 215-a of the first memory section 110-b.According to an example illustrated by circuit 400, memory cells105-b-11 through 105-b-1 n may represent a set (e.g., a column) ofmemory cells 105 of the first memory section 110-b that are coupled withor between a digit line of the first memory section 110-b (e.g., digitline 210-a-1) and a plate line of the first memory section 110-b (e.g.,plate line 215-a). According to another example illustrated by circuit400, memory cells 105-b-m1 through 105-b-mn may represent a set ofmemory cells 105 of the first memory section 110-b that are coupled withor between a different digit line of the first memory section 110-b(e.g., digit line 210-a-m) and a plate line of the first memory section110-b (e.g., plate line 215-a).

The circuit 400 may also include a second memory section 110-c, wherethe components of the second memory section are simplified forillustrative purposes and clarity in this disclosure. The second memorysection 110-c may include a set of memory cells 105-c (e.g., memorycells 105-c-11 through 105-c-mn), which may also be illustrative of anarray of memory cells 105 having m columns and n rows. Each of thememory cells 105-c may be coupled with a word line 205-b of the secondmemory section 110-c (e.g., one of word lines 205-b-1 through 205-b-n),a digit line 210-b of the second memory section 110-c (e.g., one ofdigit lines 210-b-1 through 210-b-m), and a plate line 215-b of thesecond memory section 110-c. According to an example illustrated bycircuit 400, memory cells 105-c-11 through 105-c-1 n may represent a set(e.g., a column) of memory cells 105 of the second memory section 110-cthat are coupled with or between a digit line of the memory section110-c (e.g., digit line 210-b-1) and a plate line of the second memorysection 110-c (e.g., plate line 215-b). According to another exampleillustrated by circuit 400, memory cells 105-c-m1 through 105-c-mn mayrepresent a set of memory cells 105 of the second memory section 110-cthat are coupled with or between a different digit line of the secondmemory section 110-c (e.g., digit line 210-b-m) and a plate line of thesecond memory section 110-c (e.g., plate line 215-b).

In the example of circuit 400, each of the memory cells 105-b and 105-cmay include a respective capacitor 220 and a respective cell selectioncomponent 230. A voltage at a point (e.g., a node, an intermediate node,a terminal) between the respective capacitor 220 and the respective cellselection component 230 may be identified as a respective V_(bottom), asillustrated throughout the first memory section 110-b. In some examples,one or more of the capacitors 220 may be ferroelectric capacitors asdescribed herein. Each of the memory sections 110-b and 110-c may be anexample of a memory section 110 that includes memory cells 105associated with one of a plurality of word lines 205 of the section thatis configured to selectively couple the memory cell 105 with one of aplurality of digit lines 210 of the section. The circuit 400 may be anexample of an apparatus having memory sections 110 each including memorycells 105, digit lines 210, and word lines 205 configured to selectivelycouple the memory cells 105 with one of the digit lines 210. The circuit400 may also be an example of an apparatus having a memory controller170 operable to perform various operations of the present disclosure.

Although both the first memory section 110-b and the second memorysection 110-c are illustrated as including common plate lines 215-a and215-b, respectively (e.g., common plates for each memory section 110, acommon node for each of the memory cells 105 of a memory section 110),some examples of a circuit 400 may include a separate plate lines 215-aor 215-b for each row of memory cells 105-b or 105-c (e.g.,independently accessible plate lines 215 associated with each of theword lines 205) or separate plate lines 215-a or 215-b for each columnof memory cells 105-b or 105-c (e.g., independently accessible platelines 215 associated with each of the digit lines 210).

Each of the word lines 205-a and 205-b (e.g., each of the word linesWL₁₁ through WL_(1n) and WL₂₁ through WL_(2n)) may be associated with arespective word line voltage V_(WL) as illustrated, and may be coupledwith a respective row component (e.g., row component 125-b for the firstmemory section 110-b, row component 125-c for the second memory section110-c). The row components 125-b and 125-c may couple one or more of theword lines 205-a or 205-b with various voltage sources (not shown). Forexample, the row component 125-b may selectively couple one or more ofthe word lines 205-a with a voltage source having a relatively highvoltage (e.g., a selection voltage, which may be a voltage greater than0V) or a voltage source having a relatively low voltage (e.g., adeselection voltage, which may be a ground voltage of 0V, or a negativevoltage). In another example, the row component 125-b may selectivelycouple one or more of the word lines 205-a with one of three voltagesources. In some examples, a first voltage source may have an idle orstandby voltage (e.g., a ground voltage, a relatively small positivevoltage), a second voltage source may have a selection voltage (e.g., apositive voltage greater than a ground voltage, a relatively largepositive voltage), and a third voltage source may have a deselectionvoltage (e.g., a ground voltage, a negative voltage). Some examples mayfurther include a word line equalization voltage source to supportvarious operations, which may be a fourth voltage source. Other examplesare possible in accordance with the present disclosure. The rowcomponent 125-c may couple word lines 205-b with voltage sources in amanner similar to the row component 125-b, or in a manner different fromthe row component 125-b.

Each of the digit lines 210-a and 210-b (e.g., each of the digit linesDL₁₁ through DL_(1m) and DL₂₁ through DL_(2m)) may be associated with arespective digit line voltage V_(DL) as illustrated, and may be coupledwith a respective sense component 150 (e.g., sense component 150-b,sense component 150-c). In the example of circuit 400, each of the digitlines 210-a and 210-b are illustrated as direct connections between therespective memory section 110 and the respective sense component 150(e.g., directly coupling the memory section 110-b with the sensecomponent 150-b, directly coupling the memory section 110-c with thesense component 150-c). In other examples of circuits that support thedescribed access schemes for activity-based data protection in a memorydevice, additional components or elements may be coupled with or betweena memory section 110 and a sense component 150, including an intrinsiccapacitance 240, one or more signal development components 280, or oneor more bypass lines 270, as described with reference to FIG. 2. In someexamples, the circuit 400 may also include a set of signal lines SL₁₁through SL_(1m) or SL₂₁ through SL_(2m), such as the signal line 260 asdescribed with reference to FIG. 2.

Each of the one or more plate lines 215-a or 215-b (e.g., plate linePL₁, plate line PL₂) may associated with a respective plate line voltageV_(PL) as illustrated, and may be coupled with a respective platecomponent 145 (e.g., plate component 145-b for the first memory section110-b, plate component 145-c for the second memory section 110-c). Theplate components 145-b or 145-c may couple one or more plate lines 215-aor 215-b with various voltage sources (not shown). For example, theplate component 145-b may selectively couple one or more plate lines215-a with a voltage source having a relatively high voltage (e.g., aplate high voltage, which may be a voltage greater than 0V) or a voltagesource having a relatively low voltage (e.g., a plate low voltage, whichmay be a ground voltage of 0V, or a negative voltage).

The row component 125-b, the sense component 150-b, and the platecomponent 145-b may be configured to support various access operations(e.g., read operations, write operations, rewrite operations, refreshoperations, voltage adjustment operations, dissipation operations,equalization operations) for the first memory section 110-b. Forexample, the row component 125-b may be configured to activate orotherwise apply a voltage to particular word lines 205-a. In someexamples, activating a word line 205-a may activate the cell selectioncomponent 230-a for one or more of the memory cells 105-b that arecoupled with the respective word line 205-a. For example, activating theword line 205-a-1 may activate all of the cell selection components230-a-11 through 230-a-m1 associated with memory cells 105-b-11 through105-b-m1 (e.g., a row of memory cells 105-b of the first memory section110-b).

The sense component 150-b may include a set of sense amplifiers 290-aconfigured to detect a logic state stored by respective ones of thememory cells 105-b. In some examples, the sense amplifiers 290-a maydetect a logic state stored by comparing a respective digit line voltageV_(DL) with a reference line voltage V_(RL), which may be provided tothe sense component 150-b by a reference component 285-a (e.g., viareference line 265-a).

The plate component 145-b may be configured to activate or otherwiseapply a voltage to particular one or more of the plate lines 215-a. Insome examples, operations associated with the row component 125-b, thesense component 150-b, the plate component 145-b, or the referencecomponent 285-a may be controlled at least in part by the memorycontroller 170-b.

Similarly, the row component 125-c, the sense component 150-c, and theplate component 145-c may be configured to support various accessoperations (e.g., read operations, write operations, rewrite operations,refresh operations, voltage adjustment operations, dissipationoperations, equalization operations) for the second memory section110-c. In some examples, operations associated with the row component125-c, the sense component 150-c, the plate component 145-c, or thereference component 285-b may also be controlled at least in part by thememory controller 170-b.

In the example of circuit 400, the sense components 150-b and 150-c mayeach include a separate sense amplifier 290 (e.g., sense amplifiers290-a for the first memory section 110-b, sense amplifiers 290-b for thesecond memory section 110-c) associated with each of the respectivedigit lines 210-a or 210-b (e.g., a separate sense amplifier 290 foreach column of memory cells 105). Each of the sense amplifiers 290-a and290-b may be coupled with other portions of a memory device, such as acolumn component 135, an input/output component 160, or a memorycontroller 170-b (e.g., via one or more I/O lines 295, not shown). Eachof the sense amplifiers 290-a and 290-b may be associated with arespective signal voltage V_(sig) and a respective reference voltageV_(ref), such as the associated voltages as described with reference toFIG. 2. Each of the sense amplifiers 290-a and 290-b may be coupled witha first sense amplifier voltage source (e.g., having a voltage of V_(L),which may be a ground voltage substantially equal to V₀ or a negativevoltage), and coupled with a second sense amplifier voltage source(e.g., having a voltage of V_(H), which may be greater than the voltageof V_(L)), such as those described with reference to FIG. 2.

The sense components 150-b and 150-c may, in some examples, be used tolatch signals associated with a read operation when detecting a logicstate stored by memory cells 105-b or 150-c. For example, electricalsignals associated with such latching may be communicated between thesense component 150-a (e.g., a sense amplifier 290-a) and aninput/output component 160, for example, via I/O lines 295 (not shown).In some examples, the sense components 150-a and 150-b may be inelectronic communication with the memory controller 170-b, which maycontrol various operations of the sense components 150-a and 150-b. Insome examples, activating a logical signal provided to a sense component150 may be referred to as “enabling” or “activating” the sense component150. In some examples, activating a logical signal provided to a sensecomponent 150 may be referred to, or be part of an operation known as“latching” the result of accessing memory cells 105.

In the example of circuit 400, each of the sense amplifiers 290-a and290-b may be selectively coupled or decoupled with various portions ofthe circuit 400 by various switching components. In some examples, eachof the sense amplifiers 290-a and 290-b may include a switchingcomponent configured to selectively couple or decouple the respectivesense amplifier 290-a or 290-b and a respective digit line 210-a or210-b (e.g., by activating or deactivating a logical signal). In someexamples, each of the sense amplifiers 290-a and 290-b may include aswitching component configured to selectively couple or decouple therespective sense amplifier 290-a or 290-b and a reference source, suchas the reference component 285-a or 285-b (e.g., by activating ordeactivating a logical signal).

In some examples, each of the sense amplifiers 290-a and 290-b mayinclude a switching component configured to selectively couple ordecouple the respective sense amplifier 290-a or 290-b and a respectiveequalization voltage source (e.g., by activating or deactivating alogical signal). In some examples, an equalization voltage source mayrepresent a common grounding point (e.g., a chassis ground, a neutralpoint), which may be associated with a common reference voltage having avoltage V₀, from which other voltages are defined.

Any one or more of the logical signals described with reference to thecircuit 400 may be provided by the memory controller 170-b, which may bean example of a memory controller 170 that is shared among multiplememory sections 110. Although certain switching components may sharecommon logical signals, any of the switching components may be activatedor deactivated by a logical signal that is specific to a given switchingcomponent (e.g., a logical signal specific to a particular one of thedigit lines 210-a or 210-b, a logical signal specific to a particularrow of memory cells 105, a logical signal specific to a particular oneof the digit lines 210-a or 210-b, a logical signal specific to aparticular column of memory cells 105).

Although circuit 400 is illustrated with separate reference voltagesources (e.g., reference component 285-a, reference component 285-b),other embodiments or configurations that support the described accessschemes for activity-based data protection in a memory device may employa self-referencing access scheme, where a reference voltage for readinga respective memory cell 105-b or 105-c may be provided at least in partby accessing the respective memory cell 105-b or 105-c (e.g., in asubsequent operation). In such examples, the memory cell 105-b or 150-cmay be coupled with a reference node of the respective sense amplifier290-a or 290-b.

Although the memory sections 110-a and 110-b and the sense components150-a and 150-b are illustrated with respective dashed lines asreflecting particular boundaries, such boundaries are shown forillustrative purposes only. In other words, one or more of the memorysections 110-a and 110-b and the sense components 150-a and 150-b inaccordance with the present disclosure may have boundaries differentthan the dashed boundaries shown in the circuit 400, and accordingly mayinclude more or fewer components than illustrated in the example of FIG.4.

In one example, a memory device may have more than one set of digitlines 210 coupled with a sense component 150-b, which may be selectedvia a column selection component or level selection component. Forexample, the digit lines 210-a-1 through 210-a-m of circuit 400 mayillustrate a first set of digit lines (e.g., a first set of columns, afirst level of columns) coupled with the sense component 150-b. Anotherset of digit lines (e.g., digit lines 210-c-1 through 210-c-m, notshown) may refer to a second set of digit lines (e.g., a second set ofcolumns, a second level of columns) coupled with the sense component150-b that may have a similar arrangement as the first set of digitlines (e.g., coupled with a different set of memory cells 105, notshown).

In some examples a circuit of a memory device 100 may include a columnselection component or level selection component between the sensecomponent 150-b and the first and second sets of digit lines to selectwhether a digit line 210 of the first set of digit lines is coupled withthe sense component 150-b or a digit line 210 of the second set of digitlines is coupled with the sense component 150-b. In some examples,different sets of digit lines 210 or columns may share common word lines205. In other words, in some examples, a word line 205 may activate cellselection components 230 of memory cells 105 (e.g., rows) in differentsets of digit lines 210 or columns. In some examples, different sets ofdigit lines 210 or columns may also share signal lines between a memorysection 110 and a sense component 150 (e.g., between a sense component150 and a column selection component or level selection component).Thus, a particular memory cell 105 may be accessed with a combination ofa particular word line address, a digit line or signal line address, anda column selection or level selection address (e.g., a “Y-address”).

In various examples in accordance with the present disclosure, memorycells 105 associated with the first set of digit lines and the secondset of digit lines may be considered to be part of the same memorysection 110 (e.g., digit lines 210-a-1 through 210-a-m and digit lines210-c-1 through 210-c-m being included in the first memory section110-b, digit lines 210-a-1 through 210-a-m and digit lines 210-c-1through 210-c-m sharing a common plate line 215-a), or memory cells 105associated with the first set of digit lines and the second set of digitlines may be considered to be part of different memory sections (e.g.,digit lines 210-a-1 through 210-a-m being included in the first memorysection 110-b and coupled with the plate line 215-a, and digit lines210-c-1 through 210-c-m being included in another memory section 110-dand coupled with another plate line 215-c, not shown).

In some cases, although voltage sources may be coupled with commonvoltage supplies and/or grounding points, the voltage at each of thevoltage sources coupled with a common voltage supply or common groundingpoint may be different due to various differences in the circuit 400(e.g., conductor length, conductor width, conductor resistance,conductor or other capacitance) between the respective voltage sourcesand the associated common voltage supply or common grounding point.

In some examples, the first memory section 110-b may be isolated orotherwise separated from the second memory section 110-c. For example,the digit lines 210-a may be isolated from the digit lines 210-b, theplate line 215-a may be isolated from the plate line 215-b, and the wordlines 205-a may be isolated from the word lines 205-b. In variousexamples, the row component 125-b may be separate from the row component125-c, the plate component 145-b may be separate from the platecomponent 145-c, the reference component 285-a may be separate from thereference component 285-b, or the sense component 150-b may be separatefrom the sense component 150-c. In some examples (e.g., when the firstmemory section 110-b is isolated or otherwise separated from the secondmemory section 110-c), an access operation performed on the first memorysection 110-b may not affect the second memory section 110-c. In otherwords, voltages or other signals applied to the first memory section110-b (e.g., during an access operation) may not translate into voltagesor other signals being applied to the second memory section 110-c, andvice versa. Thus, leakage charge or bias may accumulate at differentrates from one memory section 110 to another memory section 110, and avoltage adjustment operation performed on one memory section 110 may notprovide a similar effect on another memory section 110. In accordancewith aspects of the present disclosure, an access history of a set ofmemory sections 110 may be used to select a particular memory section110 for a voltage adjustment operation to mitigate the accumulation ofleakage charge or bias on the most-frequently accessed memory sections110 of a memory device.

FIG. 5 shows a timing diagram 500 illustrating operations of an exampleaccess scheme for protecting stored data in a memory device inaccordance with aspects of the present disclosure. The timing diagram500 is described with reference to components of the example circuit 400of FIG. 4, but may be illustrative of operations that may be performedwith different circuit arrangements as well.

In the example of timing diagram 500, the memory cell 105-b-11 may be aselected memory cell 105 (e.g., a selected memory cell 105-b of thefirst memory section 110-b). In other words, prior to or during theoperations of timing diagram 500, the memory cell 105-b-11 may beselected or otherwise identified (e.g., by the memory controller 170-b)for an access operation (e.g., a read operation, which in some examplesmay include or be followed by a rewrite operation) of the first memorysection 110-b. Other memory cells 105-b (e.g., memory cells 105-b-12,not shown, through 105-b-1 n) of the first memory section 110-b may benon-selected memory cells 105 (e.g., non-selected memory cells 105-b ofa column of memory cells) in the example of timing diagram 500. In theexample of timing diagram 500, the memory cell 105-b-11 may initiallystore a logic 1 state as described herein (e.g., with reference to FIG.3). In the example of timing diagram 500, the non-selected memory cell105-b-1 n may also initially store a logic 1 state as described herein(e.g., with reference to FIG. 3). With regard to the described leakageresulting from access operations, non-selected memory cells 105 may bereferred to as “victim cells” and selected memory cells 105 may bereferred to as “aggressor cells.”

In some examples, prior to initiating the operations of timing diagram500 (e.g., during an idle period, an idle interval, a standby period, astandby interval), the digit lines 210-a and the plate line 215-a of thefirst memory section 110-b may be biased at the same voltage. Matchingthe voltage of digit lines 210-a and plate lines 215-a may minimizecharge leakage in the first memory section 110-a. For example, in theexample of timing diagram 500, the digit lines 210-a and the plate line215-a of the first memory section 110-b may have an initial voltage of0V (e.g., a ground voltage, a chassis ground voltage, an equalizationvoltage), which may be provided by various voltage sources (e.g., viathe sense component 150-b, via the plate component 145-b, via a columncomponent 135, via a signal development component 280). In otherexamples, the digit lines 210-a and the plate line 215-a may be biasedat different voltages, which may or may not be equal between the digitlines 210-a and the plate line 215-a.

The timing diagram 500 may illustrate an access scheme in which the rowcomponent 125-b is configured to apply a voltage (e.g., bias) to each ofthe word lines 205-a of the first memory section 110-b one of threevoltages to support the various operations described herein (e.g., foractivating, deactivating, equalizing particular word lines 205-a or rowsof the first memory section 110-b). To support the operations of thetiming diagram 500, the row component 125-b may include variousconfigurations of voltage sources, voltage supplies, switchingcomponents, selection components, amplifiers, or voltage conversioncomponents to apply a particular voltage to particular ones of the wordlines 205-a, which in some examples may be responsive to signals orcommands from the memory controller 170-b.

A first voltage, V₁, may represent a word line idle or standby voltage.According to the example of timing diagram 500, the first voltage may,in some cases, be a ground or virtual ground voltage, and may be coupledwith a same voltage supply or chassis ground as voltage sources of thesense component 150-b or the plate component 145-b, for example.

The first voltage may have a value associated with deactivating cellselection components 230-a of the first memory section 110-b undercertain conditions. In some examples, the first voltage may have a valueof 0V, and may be referred to as VSS. In other examples, the firstvoltage may have a negative value for deactivating cell selectioncomponents 230, and may be referred to as VNWL.

A second voltage, V₂, may represent a cell access word line voltage.According to the example of timing diagram 500, the third voltage may,in some cases, be a relatively large positive voltage, and may have amagnitude large enough to activate cell selection components 230-a ofthe first memory section 110-b under certain conditions (e.g., for readoperations, for write operations, for rewrite operations, for refreshoperations). In some examples, the second voltage may be selected tohave a relatively large magnitude in order to support relatively fastaccess operations (e.g., as compared with using a lower voltage forselecting a memory cell 105-b for a read operation, write operation,rewrite operation, refresh operation). In some examples, the secondvoltage may have a value of 3.1V, and may be referred to as VCCP.

A third voltage, V₃, may represent a cell equalization or dissipationword line voltage. According to the example of timing diagram 500, thethird voltage may, in some cases, be a relatively small positivevoltage, and may have a magnitude large enough to activate a cellselection component 230-a of the first memory section 110-b undercertain conditions (e.g., for voltage adjustment operations). In someexamples, the third voltage may be selected to have a relatively smallmagnitude in order to support voltage adjustment operations or otherstates with relatively low power consumption (e.g., as compared withusing a higher voltage for voltage adjustment operations). In someexamples, the third voltage may be selected to support a relatively lowslew rate (e.g., rate of change of voltage) during the describedoperations. In some examples, the third voltage may have a value of 1.0Vto 1.2V, and may be referred to as VPWL or Vperi.

At 501, the access operation may include various initializationoperations of the first memory section 110-b, or otherwise associatedwith the first memory section 110-b. For example, at 501, the accessoperation may include selectively decoupling sense amplifiers 290-a ofthe sense component 150-b from respective equalization voltage sources(e.g., deactivating switching components between the sense amplifiers290-a and ground voltage sources, which may include deactivating logicalsignals associated with the sense component 150-b). Thus, at 501,respective signal voltages V_(sig) (e.g., voltages on the array side ofthe sense component 150-b) and reference voltages V_(ref) (e.g.,voltages on the reference side of the sense component 150-b) for thesense amplifiers 290-a may be at zero volts.

At 502, the access operation may include raising the voltage of theplate line 215-a (e.g., a common plate, a common node of memory cells105-b) of the first memory section 110-b. For example, at 502, the platecomponent 145-b may couple the plate line 215-a with a voltage sourcehaving a relatively high voltage (e.g., a plate high voltage). In someexamples, at 502, the plate component 145-b may decouple the plate line215-a from a plate low voltage source (e.g., a ground voltage source, anidle plate line voltage source, a standby plate line voltage source)prior to coupling the plate line 215-a with the voltage source havingthe relatively high voltage. Thus, at 502, the plate line voltageV_(PL,1) of the first memory section 110-b may increase from the voltageprior to 502.

In some examples, the operations of 502 may be associated with driving aleakage charge into or out of non-selected memory cells 105-b of thefirst memory section 110-b. For example, due to the difference in thevoltage of the plate line 215-a and the digit line 210-a-1 (e.g.,V_(PL,1)−V_(DL,11)) of the first memory section 110-b, leakage chargemay flow across one or more of the cell selection components 230-a-12(not shown) through 230-a-1 n associated with the memory cells 105-b-12through 105-b-1 n. Accordingly, leakage charge may flow into or out ofone or more of the capacitors 220-a-12 (not shown) through 220-a-1 n,which may alter the charge state or logic state stored by one or more ofthe non-selected memory cells 105-b-12 through 105-b-1 n (e.g., memorycells 105-b of the same column as a selected memory cell 105-b). Forexample, as compared with the charge state 305-a described withreference to FIG. 3, the operations of 502 may cause a ferroelectriccapacitor 220-a of a non-selected memory cell (e.g., one or more of thememory cells 105-b-12 through 105-b-1 n) to move along the path 360(e.g., towards charge state 305-e), which may represent a partial lossof polarization of one or more of the non-selected memory cells 105-b-12through 105-b-1 n.

In some examples, leakage charge may be driven into or out of othernon-selected memory cells 105-b of the first memory section 110-b (e.g.,memory cells 105 of other columns of the first memory section 110, onemore of memory cells 105-b-m1 through 105-b-mn) as a result of raisingthe voltage of the plate line 215-a. In some examples, raising a voltageof a plate line 215 of a memory section 110 may be associated withdriving leakage charge into or out of all memory cells 105 of the memorysection 110, whether a particular memory cell 105 is selected or not.For example, some amount of leakage charge may be driven into or out ofthe selected memory cell 105-b-11 as a result of raising the voltage ofthe plate line 215-a at 502 from a first voltage to a second highervoltage, before the cell selection component 230-a-11 is activated for adetermined access operation (e.g., a word line selection operation at503).

The leakage charge associated with such operations may be illustrated bythe voltage behavior of the non-selected memory cells 105-b of the firstmemory section 110-b (e.g., any one or more of the memory cells 105-b-12through 105-b-1 n, coupled with the digit line 210-a-1). For example, inthe absence of charge leakage, the cell bottom voltages V_(bottom,1) ofnon-selected memory cells 105-b-12 through 105-b-1 n, coupled with thedigit line 210-a-1, would generally follow the plate line voltageV_(PL,1). However, in the example of timing diagram 500, the cell bottomvoltage V_(bottom,1n) associated with the memory cell 105-b-1 n (e.g.,storing a logic 1) may not rise as high as the applied voltage V_(PL),due to charge leakage from the cell bottom of the ferroelectriccapacitor 220-a-1 n through the cell selection component 230-a-1 n tothe digit line 210-a-1. Thus, the ferroelectric capacitor 220-a-1 n (orthe capacitor 220-a of any of the other non-selected memory cells105-b-12 through 105-b-1 n) may experience a change in voltage (e.g., anaccumulated non-zero bias), illustrated by ΔVcap,1 n, which may beassociated with a change in charge state of the ferroelectric capacitor220-a-1 n (e.g., a transition from a charge state 305-a towards a chargestate 305-e).

In some examples, leakage charge may continue to flow in the firstmemory section 110-b after 502, (e.g., until the voltage of the plateline 215-a and the digit line 210-a-1 are equalized after 508, until thedifference in voltage of the plate line 215-a and the digit line 210-a-1is equal to a capacitor voltage V_(cap) of a ferroelectric capacitor220-a of a respective memory cell 105-b). The change in voltage of theferroelectric capacitor 220-a-1 n may continue to be illustrated by thevoltage ΔVcap,1 n throughout the operations of the timing diagram 500.Although leakage charge is described with reference to leakage acrosscell selection components 230, leakage may also be a result of couplingbetween intermediate nodes or cell bottoms 222 of adjacent memory cells105 (e.g., leakage as a result of a difference between V_(bottom,11) andV_(bottom,12), leakage as a result of a difference between V_(bottom,11)and V_(bottom,21)).

At 503, the operations may include a word line selection operation ofthe first memory section 110-b. For example, at 503, the row component125-b may change the word line 205-a-1 associated with the selectedmemory cell 105-b-11 (e.g., a selected word line 205-a of the firstmemory section 110-b, a selected row of the first memory section 110-b)from being biased at the first voltage (e.g., V₁, a word line idle orstandby voltage) to being biased at the second voltage (e.g., V₂, a cellaccess word line voltage). In other words, the operations of 503 may beassociated with activating or selecting the word line 205-a-1 (e.g., ofthe first memory section 110-b), which may include causing or initiatinga transition in the bias applied to the word line 205-a-1 (e.g.,V_(WL,11)). In some examples, the operations of 503 may be accompaniedby determining to access the memory cell 105-b-11 of the memory section110-b (e.g., a determination by the memory controller 170-b), orotherwise identifying the memory cell 105-b-11 for performing an accessoperation. In some examples, the operations of 503 may be associatedwith selectively coupling the ferroelectric capacitor 220-a-11 with thedigit lines 210-a-1. In some examples, the operations of 503 may bereferred to as selecting the memory cell 105-b-11.

Because the word line 205-a-1 is coupled with the cell selectioncomponent 230-a-11, the cell selection component 230-a-11 may beactivated as a result of the operations of 503. In other words, as aresult of the operations of 503, the capacitor 220-a-11 may beselectively coupled with the digit line 210-a-1. Thus, charge may flowbetween the memory cell 105-b-11 and the digit line 210-a-1 based on thelogic state stored by the memory cell 105-b-11 (e.g., based on apolarization state of the capacitor 220-a-11). Accordingly, in theexample of the timing diagram 500, the voltage of the digit line 210-a-1(e.g., V_(DL,1)) may rise as charge is shared with the digit line210-a-1. In some examples (e.g., when the first memory section 110-b iscoupled with the sense component 150-b), the signal voltage at the senseamplifier 290-a-1 (e.g., V_(sig,1)) may also rise and may be equal toV_(DL,1) after 503. Thus, the operations of 503 may be an example ofperforming an access operation on the selected memory cell 105-b-11 bycausing the row component 125-b (e.g., a row decoder) to activate theword line 205-a-1. In some examples, the operations of 503 may also beassociated with performing an access operation on other memory cells 105in a row of memory cells 105 (e.g., memory cells 105-b-21 through105-b-m1).

At 504, the operations may include providing a reference voltage to thesense component 150-b. For example, at 504, the reference component285-a may couple the reference line 265-a of the first memory section110-b with a voltage source providing a reference voltage. The referencevoltage may, in some cases, be selected as a value (e.g., an average)between the signal voltage generated when reading a memory cell 105-bthat stores a logic 0 (e.g., V_(sig) when reading a logic 0) and thesignal voltage generated when reading a memory cell 105-b that stores alogic 1 (e.g., V_(sig) when reading a logic 1). In some examples, at504, the access operation may include the reference component 285-adecoupling the reference line 265-a from a ground voltage source priorto coupling the reference line 265-a with the voltage source providingthe reference voltage. Thus, at 504, the voltage of the reference line265-a (e.g., V_(RL,1)) may increase from the voltage prior to 504 (e.g.,an idle or standby reference line voltage). In some examples, thereference voltage at the sense amplifier 290-a-1 (e.g., V_(ref,1)) mayalso rise and may be equal to V_(RL,1) after 504. In other examples ofaccess schemes that support self-referencing read operations (notshown), the illustrated operations at 504 may be replaced with one ormore operations that develop a reference signal using the memory cell105-b-11 (e.g., using a selected memory cell 105-b).

At 505, the operations may include latching the result of detecting thelogic state stored by the memory cell 105-b-11. For example, at 505, thesense amplifiers 290-a may be activated (e.g., by activating a logicalsignal to the sense component 150-b), which may couple the senseamplifier 290-a-1 with a high sense amplifier voltage source (e.g., avoltage source at a voltage V_(H)) and may couple the sense amplifier290-a-1 with a low sense amplifier voltage source (e.g., a voltagesource at a voltage V_(L)). In some examples, the operations at 505 mayinclude isolating (e.g., decoupling) the sense amplifier 290-a from thefirst memory section 110-b (e.g., by deactivating the switchingcomponent between the sense amplifiers 290-a and the first memorysection 110-b), which may isolate a signal node 291 of the senseamplifier 290-a-1 from the memory cell 105-b-11. In some examples, theoperations at 505 may include isolating (e.g., decoupling) the senseamplifiers 290-a from the reference component 285-a (e.g., bydeactivating a switching component between the sense amplifiers 290-aand the reference component 285-a), which may isolate a reference node292 of the sense amplifier 290-a-1 from the reference component 285-a.In some examples, isolating the sense amplifiers 290-a from the firstmemory section 110-b or the reference component 285-b or both may beperformed before activating the sense amplifiers 290-a.

In the example of timing diagram 500, where V_(sig,1) is greater thanV_(ref,1) at 505, the V_(sig,1) may rise to the voltage V_(H) andV_(ref,1) may fall to the voltage V_(L) as a result of the operations of505. The voltages of V_(sig,1) or V_(ref,1) (e.g., V_(H) or V_(L)) maybe provided as an output of the sense component 150-b (e.g., to a columncomponent 135, to an input/output component 160, to the memorycontroller 170-b). In some examples, any one or more of the operationsof 501 through 505 may be referred to as a read operation.

At 506, the operations may include coupling the sense amplifier 290-a-1with the first memory section 110-b. For example, at 506, the operationsmay include activating a switching component between the sense amplifier290-a-1 and the first memory section 110-b, which may couple a signalnode 291 of the sense amplifier 290-a-1 with the memory cell 105-b-11.Accordingly, the voltage of the digit line 210-a-1 (e.g., V_(DL,11)) mayrise to voltage of the high sense amplifier voltage source (e.g.,V_(H)), which in some examples may also be the voltage of the plate linehigh voltage source (e.g., as activated at 502).

At 507, the operations may include lowering the voltage of the plateline 215-a of the first memory section 110-b. For example, at 507, theplate component 145-b may couple the plate line 215-a with a voltagesource having a relatively low voltage (e.g., a plate line low voltage,a ground voltage, a virtual ground voltage). In some examples, at 507,the plate component 145-b may decouple the plate line 215-a from avoltage source having a relatively high voltage prior to coupling theplate line 215-a with the voltage source having the relatively lowvoltage. Thus, at 507, the plate line voltage may drop from the voltageprior to 507 (e.g., returning to an idle or standby plate line voltage).

In some examples, the operations of one or both of 506 or 507 may bereferred to as a rewrite operation, or be otherwise included in arewrite operation of the memory cell 105-b-11. For example, at 507, thevoltage applied across the ferroelectric capacitor 220-a-11 (e.g.,V_(cap)) may be equal to the difference between the voltage of the digitline 210-a-1 (e.g., V_(DL,11)) and the plate line 215-a (e.g., V_(PL,1))of the first memory section 110-b. In some examples, the voltage appliedacross the ferroelectric capacitor 220-a-11 may correspond to thevoltage 315 described with reference to FIG. 3, which may correspond toa positive saturation voltage. In other words, the operations of one orboth of 506 and 507 may be associated with rewriting the memory cell105-b-11 with a logic 1 state (e.g., returning the memory cell 105-b-11to the logic state stored prior to the operations of timing diagram500). Thus, after the operations of 507, the ferroelectric capacitor220-a-11 may be positively saturated. In other examples, the operationsof any one or more of 501 through 507, including a rewrite operation,may be referred to as a single access operation (e.g., a“read-plus-rewrite” operation). In some examples, operations of one orboth of 506 or 507 may be performed separately from a read operation,and may alternatively be referred to as a “write” operation.

In some examples, the operations of 507 may also be associated withdriving a leakage charge into non-selected memory cells 105. Forexample, due to the difference in the voltage of the digit line 210-a-1and the plate line 215-a (e.g., V_(DL,11)−V_(PL,1)) of the first memorysection 110-b, leakage charge may flow across one or more of the cellselection components 230-a-12 through 230-a-1 n of the memory cells105-b-12 through 105-b-1 n (e.g., of a column of memory cells 105-b ofthe first memory section 110-b). Accordingly, leakage charge may flowinto one or more of the capacitors 220-a-12 through 220-a-1 n, which mayalter the logic state stored by one or more of the non-selected memorycells 105-b-12 through 105-b-1 n of the first memory section 110-b.

In some examples, the leakage charge associated with the operations of507 may flow in a direction opposite from a flow of leakage chargeassociated with the operations of 502. In other words, as compared withthe charge state 305-e described with reference to FIG. 3, theoperations of 507 may cause a ferroelectric capacitor 220-1 of anon-selected memory cell (e.g., one or more of the memory cells 105-b-12through 105-b-1 n) to move towards the charge state 305-f In someexamples, leakage charge or bias may continue to accumulate after 507,(e.g., until the voltage of the plate line 215-a and the digit line210-a-1 are equalized after 508, until the difference in voltage of theplate line 215-a and the digit line 210-a-1 of the first memory section110-b is equal to a capacitor voltage V_(cap) of a respective memorycell 105-b).

At 508, the operations may include equalizing the input nodes of thesense amplifiers 290-a. For example, at 508, the operations may includeactivating switching components between the sense amplifiers 290-a andrespective equalization voltage sources, which may selectively couplethe sense amplifiers 290-a with the respective equalization voltagesources. In some examples, the operations at 508 may includedeactivating the sense component 150-a (e.g., deactivating the senseamplifiers 290-a before equalizing the input nodes of the senseamplifiers 290-a). For example, deactivating the sense component 150-bat 508 may include decoupling the sense amplifiers 290-a from a highsense amplifier voltage source (e.g., a voltage source at a voltageV_(H)) and decoupling the sense amplifiers 290-a from a low senseamplifier voltage source (e.g., a voltage source at a voltage V_(L)).Thus, at 508, the signal voltages V_(sig) and reference voltages V_(ref)for the sense amplifiers 290-a may be biased at zero volts. In someexamples (e.g., when the sense component 150-b is coupled with the firstmemory section 110-b), each of the digit lines 210-a may also be biasedat zero volts as a result of the operations of 508.

In some examples, the operations at 508 may include coupling the senseamplifiers 290-a with the reference component 285-a. For example, theoperations at 508 may include activating switching components betweenthe sense amplifiers 290-a and the reference component 285-a, which mayselectively couple a reference node 292 of the sense amplifiers 290-awith the reference component 285-a. In some examples, the referencecomponent 285-a may couple the reference line 265-a with a groundvoltage source before or after coupling the sense amplifiers 290-a withthe reference component 285-a.

At 509, the operations may include deactivating the selected word line205-a-1. For example, at 509, the row component 125-b may change theselected word line 205-a-1 from being biased at the second voltage(e.g., V₂, the cell access word line voltage) to being biased at thefirst voltage (e.g., V₁, a word line idle or standby voltage). In someexamples, the operations of 509 may be associated with selectivelydecoupling the ferroelectric capacitors 220-a-11 from the respectivedigit line 210-a-1.

Although illustrated as separate operations occurring at differenttimes, certain operations may occur simultaneously, concurrently, or ina different order.

In some examples, various operations may be advantageously initiatedsimultaneously to reduce the amount of time for sensing a logic state ofthe memory cell 105-b. For example, any two or more of raising thevoltage of the plate line 215-a at 502, activating the word line 205-a-1at 503, or providing a reference voltage to the sense component 150-a at504, may occur in a different relative order, occur during overlappingdurations, or occur simultaneously.

Additionally or alternatively, isolating the sense amplifier 290-a-1from the first memory section 110-b and isolating the sense amplifiers290-a from the reference component 285-a may occur in a different order,occur during overlapping durations, or occur simultaneously.Additionally or alternatively, coupling the sense amplifier 290-a-1 withthe first memory section 110-b and lowering the voltage of the plateline 215-a at 507 may occur in a different order, occur duringoverlapping durations, or occur simultaneously. Additionally oralternatively, any two or more of equalizing the input nodes of thesense amplifiers 290-a, coupling the sense amplifiers 290-a with thereference component 285-a, or deselecting the word line 205-a-1 at 509may occur in a different relative order, occur during overlappingdurations, or occur simultaneously.

As illustrated by the cell bottom voltage of a non-selected memory cell105-b (e.g., V_(bottom,1n)) after 509, a cell selection component 230-aof non-selected memory cells 105-a (e.g., one or more of the memorycells 105-b-12 through 105-b-1 n, other memory cells 105 of othercolumns) may be deactivated, but leakage charge may nonetheless flowthrough the respective deactivated cell selection components 230-aduring an access operation associated with the selected memory cell105-b-11 (e.g., during the operations of any one or more of 501 through509). In the example of ferroelectric memory cells 105-b, the leakagecharge or bias may accumulate at the ferroelectric capacitors 220-a ofthe non-selected memory cells 105-b, which may alter the polarization ofthe ferroelectric capacitors 220-a (e.g., as illustrated by the non-zerovalue of ΔV_(cap,1n) after 509).

For example, when the ferroelectric capacitor 220-a-1 n of non-selectedmemory cell 105-b-1 n is at a charge state 305-a (e.g., storing a logic1), leakage charge or bias associated with an access operation on theselected memory cell 105-b-11 may cause the charge state of thenon-selected memory cell 105-b-1 n to follow at least a portion of thepath 360 described with reference to FIG. 3. In some examples, a firstaccess operation (e.g., one or more of the operations of 501 through509) on the selected memory cell 105-b-11 may cause the ferroelectriccapacitor 220-a-1 n the memory cell 105-b-1 n to approach or reach thecharge state 305-e described with reference to FIG. 3, which maycorrespond to the level of the voltage ΔV_(cap,1n).

In the event that non-selected memory cell 105-b-1 n remains asnon-selected for subsequent access operations (e.g., following theoperations of 509, not shown) for other selected memory cells 105-b ofthe first memory section 110-b, the charge state of memory cell 105-b-1n may continue along the path 360 as leakage charge or bias continues toaccumulate, until reaching charge state 305-c described with referenceto FIG. 3, for example (e.g., accumulating a larger ΔV_(cap)). Thecharge state 305-c may illustrate a substantial loss of polarization,which may illustrate a loss of data at the memory cell 105-b-1 n fromsuch accumulated leakage charge or bias. In an illustrative example, fora memory device 100 that performs access operations every 150nanoseconds, 100 microseconds may be equivalent to around 667 accessoperations.

In some examples, the cumulative leakage across successive accessoperations may be on the order of hundreds of millivolts over a timeperiod of tens or hundreds of microseconds, depending on the leakagecharacteristics of the circuit 400. However, operations may be performedafter access operations on selected memory cells 105-b (e.g., after theoperations of one or more of 501 through 509) to encourage or otherwisesupport the dissipation of leakage charge or bias from the non-selectedmemory cells 105-b, which may reduce or eliminate data loss that mayotherwise result from an accumulation of leakage charge or bias.

For example, at 510, the operations may include activating each of theword lines 205-a-1 through 205-a-n of the first memory section 110-b(e.g., for a voltage adjustment operation). For example, at 510, the rowcomponent 125-b may change from each of the word lines 205-a beingbiased at the first voltage (e.g., V₁, a word line idle or standbyvoltage) to being biased at the third voltage (e.g., V₃, a cellequalization or dissipation word line voltage).

In some examples, the operations of 510 may be associated withselectively coupling each of the ferroelectric capacitors 220-a with therespective digit lines 210-a (e.g., with a relatively low magnitudeselection voltage).

In some examples, each of the digit lines 210-a and the plate line 215-amay be biased at a same voltage (e.g., a ground voltage). Thus, as aresult of the operations of 510, each of the ferroelectric capacitors220-a may be equalized (e.g., because the respective cell selectioncomponents 230-a were activated by the word line idle or standbyvoltage). Thus, the operations of 510 may be an example of performing avoltage adjustment operation on one or more of the memory cells 105-b-11through 105-b-mn by causing the row component 125-b (e.g., a rowdecoder) to activate one or more of the word lines 205-a (e.g.,dissipating any accumulated leakage charge or bias on the memory cells105-b). Accordingly, after the operations of 510, each of theferroelectric capacitors 220-a may be returned to an equalized state(e.g., having a respective capacitor voltage V_(cap)=0V).

At 511, the operations may include idling each of the word lines 205-a-1through 205-a-n. For example, at 511, the row component 125-b may changefrom each of the word lines 205-a being biased at the third voltage(e.g., V₃, a cell equalization or dissipation word line voltage) tobeing biased at the first voltage (e.g., V₁, a word line idle or standbyvoltage). In some examples, the operations of 511 may be associated withselectively decoupling each of the ferroelectric capacitors 220-a withthe respective digit lines 210-a (e.g., with a relatively low magnitudeselection voltage). In some examples, the operations of 510 and 511 maybe referred to collectively as a voltage adjustment operation.

As illustrated by the cell bottom voltage of the memory cells 105-bafter 511, an accumulated leakage charge or bias (e.g., at thenon-selected memory cell 105-b-1 n) may be dissipated (e.g., asillustrated by the zero value of ΔV_(cap,1-n) at the end of the timingdiagram 500). Thus, as illustrated by the example of timing diagram 500,operations may be performed after access operations on a selected memorycell 105 (e.g., any one or more of the operations 501 through 509) toencourage or otherwise support the dissipation of leakage charge fromnon-selected memory cells 105, which may reduce or eliminate data lossthat may otherwise result from an accumulation of leakage charge orbias.

The order of operations shown in the timing diagram 500 is forillustration only, and various other orders and combinations of stepsmay be performed in accordance with the present disclosure. Further, thetiming of the operations of the timing diagram 500 is also forillustration purposes only, and is not meant to indicate a particularrelative duration between one operation and another. Various operationsmay occur over a duration or time interval that is relatively shorter orrelatively longer than illustrated in various embodiments of accessschemes for activity-based data protection in a memory device inaccordance with the present disclosure.

The transitions of the logical signals of the timing diagram 500 areillustrative of transitions from one state to another, and generallyreflect transitions between a disabled or deactivated state (e.g., state“0”) and an enabled or activated state (e.g., state “1”) as associatedwith a particular numbered operation. In some examples, the states maybe associated with a particular voltage of the logical signal (e.g., alogical input voltage applied to a gate of a transistor operating as aswitch), and the change in voltage from one state to another may not beinstantaneous. Rather, in some examples, a voltage associated with alogical signal may follow a ramping behavior, or time-constant (e.g.,logarithmic or exponential) behavior over time from one logical state toanother.

In some examples, the transition of a component from one state toanother may be based on characteristics of the associated logicalsignal, including the voltage level of the logical signal or thetransition characteristics of the logical signal itself. Thus, thetransitions shown in the timing diagram 500 are not necessarilyindicative of an instantaneous transition. Further, the initial state ofa logical signal associated with a transition at a numbered operationmay have been arrived during various times preceding the numberedoperation while still supporting the described transitions andassociated operations. Although logical signals are described as atransition between logical states, the voltage of a logical signal maybe selected to operate a component at a particular working point (e.g.,in an active region or in a saturation region), and may be the same as,or different from a voltage of other logical signals.

A row component 125 may be configured in various ways to support theoperations of timing diagram 500. For example, a row component 125 maybe designed such that applying a positive selection voltage to aselected one of the word lines 205 during an access operation may beaccompanied by applying a negative deselection voltage to each of thenon-selected word lines 205 (e.g., with or without applying anintervening ground voltage before applying a selection or deselectionvoltage) during the access operation. In another example, a rowcomponent 125 may be designed such that applying a positive selectionvoltage to a selected one of the word lines 205 during an accessoperation may be accompanied by applying a ground or 0V deselectionvoltage to each of the non-selected word lines 205 during the accessoperation. In another example, a row component 125 may be designed forapplying a positive selection voltage to a single selected one of theword lines 205 during an access operation, without applying adeselection voltage to each of the non-selected word lines 205 duringthe access operation. In some examples, a row-component may separatelyapply a selection or other activation voltage to each of the word lines205 perform a voltage adjustment operation on each of the word lines205.

Although the described operations for equalizing or dissipating anaccumulated charge or bias (e.g., the operations of 510 and 511) areillustrated in the timing diagram 500 as occurring after a particularaccess operation (e.g., based on performing at least one accessoperation), a memory device in accordance with examples of the presentdisclosure may perform such operations (e.g., voltage adjustmentoperations) on a section-by-section basis based on an access history ofa set of memory sections 110 (e.g., a set of memory sections 110 of amemory device 100, a set of memory sections 110 in one of a set of banksof a memory device 100). By selecting a particular memory section 110for such operations according to a memory section access history, amemory device 100 may operate more efficiently than when such operationsare performed, for example, without consideration of an access historyof a set of memory sections 110.

FIGS. 6A and 6B shows flowcharts illustrating a method 600-a and amethod 600-b that may support access schemes for activity-based dataprotection in a memory device in accordance with various embodiments ofthe present disclosure. The operations of the methods 600-a and 600-bmay be performed according to the methods and apparatuses described withreference to FIGS. 1 through 5. In some examples, the operations ofmethods 600-a or 600-b may be implemented by one or more componentsillustrated in a memory device 100, a circuit 200, or a circuit 400. Forexample, operations of methods 600-a or 600-b may be performed at leastin part by a memory controller 170, one or more row components 125,other components of a memory device 100, or various combinations thereofas described with reference to FIGS. 1 through 5. In some examples, amemory device 100, or one or more subcomponents thereof (e.g., a memorycontroller 170), may execute a set of instructions to control thefunctional elements of the device (e.g., voltage supplies, logicalsignals, transistors, amplifiers, switching components, selectioncomponents) to perform the functions described below. Additionally oralternatively, the memory device 100, or one or more subcomponentsthereof, may perform some or all of the functions described below usingspecial-purpose hardware. In some examples, method 600-a or method 600-bmay be performed by a memory device 100 having memory cells 105 thatinclude ferroelectric capacitors 220. The method 600-a or the method600-b may be referred to as implementing a Wordline-Only Refresh (WOR).

The method 600-a may be an example of performing a voltage adjustmentoperation (e.g., a dissipation operation, an equalization operation) inaccordance with examples of the present disclosure.

At 605, the method 600-a may include determining a quantity of accessoperations performed on each of a plurality of memory sections 110 of amemory device 100. For example, one or more memory controllers 170 mayhave a storage component that, for each of a set of memory sections 110,tracks a number of access operations performed on the respective memorysection 110. In one example, each memory section 110 may be associatedwith an 11-bit counter, which may count a number of access operations(e.g., up to 2048 access operations) before an overflow or latch to amaximum value. As used herein, a set of memory sections 110 may refer toall of the memory sections 110 of a memory device 100, all of the memorysections 110 of a particular subset of memory sections 110 of a memorydevice 100, all of the memory sections 110 of a particular bank ofmemory sections 110 of a memory device 100, or other sets of memorysections 110 (e.g., sets of memory sections 110 that may supportperforming separate instances of the method 600-a or 600-b).

In various examples, determining a quantity of access operations at 605may include accumulating a count of certain types of access operations(e.g., only read operations, only write operations, only write andrewrite operations, only precharge operations) for each of the memorysections 110, or may include accumulating a count of any of a group ofaccess operations (e.g., any of a read operation, a write operation, arewrite operation, or a precharge operation, or a combination thereof).The accumulated count for each memory section 110 may start at a valueof zero (e.g., upon powering a memory device 100, when initializing amemory device 100), and may be incremented to a higher value (e.g., anext larger integer) each time an access operation is performed on therespective memory section 110.

In some examples, access operation counts may be accumulated and storedat a first memory controller 170 of a memory device (e.g., a commonmemory controller 170, a shared memory controller 170), and madeavailable to one or more other memory controllers 170 (e.g., via a busbetween memory controllers 170). In some examples, determining thequantity of access operations at 605 may include the second memorycontroller 170 (e.g., a memory controller 170 responsible for performingactivity-based voltage adjustment operations) receiving quantities ofaccess operations performed on each of a set of memory sections 110 fromthe first memory controller 170 (e.g., via a bus), or a set of memorycontrollers 170 (e.g., where a memory controller 170 maintains a countof access operations for a single memory section 110).

At 610 the method 600-a may include selecting one of the sections (e.g.,one of the memory sections 110 of the memory device 100) for a voltageadjustment operation (e.g., an equalization operation, a dissipationoperation) based on the determined quantity of access operationsperformed on each of the memory sections 110. For example, referring tocomponents of the circuit 400, at 610 the memory controller 170-b maydetermine to perform a voltage adjustment operation (e.g., of a memorydevice 100 that includes the circuit 400) on either the first memorysection 110-b or the second memory section 110-c based on which of thememory sections 110 has been most-frequently accessed (e.g., a memorysection 110 associated with a highest value of an incremented counter ofaccess operations, a memory section 110 having been accessedmost-frequently since a prior voltage adjustment operation on therespective memory section 110).

In some examples, the operations of 610 may be based on or triggered bya timer, a counter, or some other determination or indication ofperiodic or aperiodic interval. For example, a memory controller 170 mayinclude a timer of the memory device 100. In some examples, the timermay be dedicated to voltage adjustment operations. In other examples,the timer may refer to a general-purpose clock or timer of a memorycontroller 170, a general-purpose clock or timer of some other componentof a memory device 100, or a timer or clock of a device that includesthe memory device 100 (e.g., a processor clock of a computer thatincludes the memory device). In some examples, a memory controller 170may establish a connection with, or otherwise receive or identify asignal associated with a general-purpose timer or clock, such asreceiving timer or clock information, or cycles of a general-purposeclock, via a bus of the memory device 100. In various examples, thetimer may count time in units of seconds, in units of clock cycles, orany other temporal unit. In some example, the timer may be referred toas a counter, and may be used to generally track a periodic interval.

In some examples, the operations of 610 may be based on or triggered bya different type of counter, such as a counter that tracks a totalnumber of access operations performed on a memory device 100 or a bankof a memory device 100. Such a counter may accumulate a count of anyaccess operation performed by the memory device (e.g., on all memorysections 110 of the memory device, of a certain subset of memorysections 110 of the memory device), or such a counter may accumulate acount of certain types of access operations (e.g., only read operations,only write operations, only write and rewrite operations, only prechargeoperations). Thus, in various examples, the method 600-a may beperformed according to temporal intervals or non-temporal voltageadjustment intervals.

In some examples, a value of the timer or counter to trigger operationsof 610 may be representative of or based on a duration or other intervalsince the memory device 100 was powered on (e.g., when determining afirst voltage adjustment operation, after powering a memory device 100).Additionally or alternatively, a value of the timer or counter totrigger the operations of 610 may be representative of or based on aduration or other interval since a prior voltage adjustment operationwas performed (e.g., on any of the memory sections 110 of the memorydevice 100, on another memory section 110 of a bank of memory sections110). A duration of such a timer may be fixed (e.g., predetermined,preconfigured, static), or a duration of such a timer may be variable(e.g., dynamic, calculated based on operating conditions, determinedbased on an operating mode or operating state).

In some examples, the operations at 610 may include determining toselect one of the memory sections 110 for a voltage adjustment operationbased on a total number of access operations performed on the memorydevice (e.g., since a prior voltage adjustment operation was performed).In other words, in some examples, the section selection operations of610 may be based on or triggered by a determined quantity of accessoperations of a memory device 100 (e.g., a quantity of a particular typeof access operation across all memory sections 110 of a memory device100, a quantity of a particular set of access operation types across allmemory sections 110 of a memory device 100), such as after every tenaccess operations of the memory device 100, every one hundred accessoperations of the memory device 100, every thousand access operations ofthe memory device 100, and so on.

In various examples, triggering the operations of 610 based on adetermined quantity of access operations of a memory device 100 may bean alternative to a triggering based on a periodic interval associatedwith a timer, or may be combined with a triggering based on a periodicinterval associated with a timer. For example, the operations at 610 mayinclude determining to select a memory section 110 for a voltageadjustment operation based the earlier of an elapsed duration since aprior voltage adjustment operation or a total number of accessoperations performed by the memory device 100 since a prior voltageadjustment operation exceeding a threshold. The operations at 610 may bereferred to as or may include determining to select a memory section 110for performing a voltage adjustment operation, a dissipation operation,or an equalization operation (e.g., based on a value of a timer, basedon a value of a counter, based on a number of access operationsperformed on all of the memory sections 110 of a memory device 100,based on a number of access operations performed on all of the memorysections 110 of a bank of a memory device 100).

In some examples, a value of the timer or counter (e.g., a voltageadjustment interval, a duration between voltage adjustment operations)to trigger the operations of 610 may be based on an operating mode of amemory device 100, where some operating modes may be associated with adifferent (e.g., shorter or longer) duration between voltage adjustmentoperations than other operating modes. In various examples, an intervalbetween voltage adjustment operations may be selected or calculatedbased on one or more operating conditions such as access rate, voltagestates, logic states, operating temperatures, power consumption, orothers, or some combination thereof.

For example, in a high-speed access mode, where relatively many accessoperations are being performed by a memory device 100 or a bank of amemory device in a given amount of time, a determined value of a timeror counter (e.g., a voltage adjustment operation interval) associatedwith the described voltage adjustment operations may be shortened (e.g.,dynamically, in response to a chance in operating mode) to mitigate dataloss from potential leakage charge or bias. In a low-power access mode,which may be associated with relatively few access operations beingperformed by a memory device 100 in a given amount of time, an intervalbetween voltage adjustment operations may be lengthened (e.g.,dynamically, in response to a chance in operating mode) to reduce powerconsumption (e.g., power consumption associated with activating wordlines 205 or equalizing a bias across memory cells 105).

In another example, a memory device 100 may detect conditions wherememory cells 105 may be more sensitive to leakage charge or bias. Suchconditions may include conditions where non-selected cell selectioncomponents 230 may permit more leakage, conditions where bias acrossnon-selected memory cells 105 may be higher, conditions where memorystorage elements of memory cells 105 may be more susceptible to loss ofpolarization, and others. A memory device 100 may accordingly operate ina mode associated with the heightened sensitivity to leakage charge orbias. In such a mode, the memory device 100 may use a shortened voltageadjustment interval for triggering the operations of 610 to mitigatedata loss from potential leakage charge or bias.

According to various examples of the present disclosure, a selection ofa most-frequently accessed memory section 110 may be configured toaccommodate a selection from as many memory sections 110 are included ina memory device 100, or a selection from a number of memory sections 110included in a defined portion of a memory device 100 (e.g., a bank of amemory device 100, a subset of memory sections 110 of a memory device).An interval between voltage adjustment operations according to such aselection may be set or defined such that the voltage adjustmentoperations are performed on respective memory sections 110 quicklyenough to handle a heavy burst of access operations on a particularmemory section 110, even under conditions experienced in a maliciousattack of a memory device 100.

In one example, a memory device 100 (e.g., a bank of a memory device100) may include 32 memory sections 110, and the memory device mayperform a voltage adjustment operation every N access operations (e.g.,on the bank of the memory device 100). In a worst-case analysis relatedto the accumulation of leakage charge or bias (e.g., as a result of amalicious attack), at a particular condition (e.g., point in time) eachof the 32 memory sections 110 may be considered to have been accessed byN−1 access operations since a prior voltage adjustment operation on arespective memory section 110. In other words, because every time acounter of a memory section 110 is cleared (e.g., following a voltageadjustment operation on the memory section 110), there are N furtheraccesses before the next voltage adjustment operation, up to N−1 accessoperations may be used to restore a cleared counter and 1 more accessoperation may result in another of the counters to be selected for avoltage adjustment operation (e.g., a most-frequently accessed memorysection 110), and subsequently reset.

From the particular point in time where each of the 32 memory sections110 have a counter value of N−1, a memory section 110 having a performedvoltage adjustment operation may be discarded (e.g., dropped from theworst-case analysis), and a subsequent set of N access operations on thememory sections 110 may be divided between the memory sections 110 whichhaven't been adjusted (e.g., prior to a next voltage adjustmentoperation).

Such operations may continue until a last of the 32 memory sections 110is selected for a voltage adjustment operation. At such a condition, thelast of the memory sections 110 will have accumulated a sum of(N−1)+(N/31)+(N/30)+ . . . +(N/2)+(N/1) access operations since the lastvoltage adjustment operation on the last memory section 110. In otherwords, in the worst case analysis of the described example of anactivity-based voltage adjustment approach, a memory section 110 may besubject to approximately 5*N access operations over 32 voltageadjustment intervals prior to a voltage adjustment operation beingperformed.

Thus, the described operations for activity-based voltage adjustmentoperations may be significantly more effective than an ordered selectionthat cycles through memory sections 110 in a particular order (e.g., apredefined order of memory sections 110 that is not based on a historyof access operations). For example, for the same memory device 100having 32 memory sections 110, a worst case analysis may need toconsider a continuous accessing of the same memory section 110 betweeninstances where a particular memory section 110 is selected for avoltage adjustment operation. In other words, a particular memorysection may be subject to approximately 32*N access operations over 32voltage adjustment intervals, which is significantly more than the 5*Naccess operations when using the activity-based approach for selectingmemory sections for a voltage adjustment operation. Thus, the describedactivity-based selection of a memory section 110 for a voltageadjustment operation may accumulate fewer access operations in a memorysection 110 between voltage adjustment operations for a given voltageadjustment interval (e.g., duration or other period between voltageadjustment operations), or may use a longer voltage adjustment intervalto accommodate a maximum number of access operations on a particularmemory section 110 between voltage adjustment operations.

In some examples, a selection of a most-frequently accessed memorysection 110 may be applied to different subsets of memory sections 110of a memory device 100, which may include a first memory controller 170performing aspects of voltage adjustment operations according to aselection from a first subset of the memory sections 110 (e.g., a firstbank), and a second memory controller 170 performing aspects of voltageadjustment operations according to a selection from a second subset ofthe memory sections 110 (e.g., a second bank). In some examples, aspectsof performing voltage adjustment operations according to selections fromdifferent subsets of memory sections 110 may be performed by a samememory controller 170 (e.g., a memory controller 170 shared acrossmultiple banks).

At 615 the method 600-a may include performing a voltage adjustmentoperation (e.g., an equalization operation, a dissipation operation) onthe selected section (e.g., a most-frequently accessed memory section110). For example, at 615, the memory device 100 may perform aspects ofthe operations of 510 and 511 described with reference to the timingdiagram 500 of FIG. 5 and the circuit 400 of FIG. 4. (e.g., selecting oractivating word lines of the selected memory section 110, equalizing abias across memory cells 105 of the memory section 110). In other words,in some examples, the operations of 610 described with reference tomethod 600-a (e.g., selecting a memory section 110 for a voltageadjustment operation) may occur between the operations of 509 and 510described with reference to timing diagram 500 (e.g., after performingone or more access operations on a memory cell 105 of a memory section110, before performing a voltage adjustment operation). Thus, in someexamples the operations of 610 may refer to a decision or trigger toperform the operations of 509 and 510 of the timing diagram 500.

In some examples, performing the voltage adjustment operation at 615 mayinclude activating each of the plurality of word lines 205 or each ofthe cell selection components 230 of the selected memory section 110. Insome examples, the voltage adjustment operation may include a memorycontroller (e.g., memory controller 170) activating switching components(e.g., cell selection components 230) associated with respective ones ofthe memory cells 105 of the selected memory section 110 to couplestorage elements (e.g., capacitors 220) of each of the memory cells 105of the selected memory section 110 with an access line (e.g., a digitline 210) of the selected memory section 110.

In some examples, activating the word lines 205 or the cell selectioncomponents 230 at 615 includes applying a selection bias (e.g., via wordlines 205) with a magnitude that is less than a selection biasassociated with an access operation. For example, access operations suchas read or write operations may be associated with a relatively highmagnitude word line voltage or cell selection voltage (e.g., a secondvoltage V₂, VCCP, 3.1V). In comparison, activating word lines 205 orcell selection components 230 for a voltage adjustment operation at 615may be associated with a relatively low magnitude word line voltage orcell selection voltage (e.g., a third voltage V₃, VPWL, Vperi, 1.0V to1.2V).

Thus, a voltage adjustment operation of 615 may include applying aselection voltage having a magnitude that is less than a selectionvoltage associated with an access operation.

In some examples, the operations at 615 may be associated withperforming an equalization operation on the selected memory section 110by equalizing a bias or voltage across storage elements (e.g.,capacitors 220) of each of the memory cells 105 of the selected memorysection 110. Performing the equalization operation may includeselectively coupling each of the memory cells 105 of the selected memorysection 110 with an access line (e.g., a digit line 210) of the selectedmemory section 110 by activating cell selection components 230associated with respective ones of the memory cells 105 of the selectedmemory section 110.

In some examples, equalizing the bias across a respective one of thememory cells 105 may include biasing a digit line 210 coupled with therespective memory cell 105 to a ground voltage and biasing a common node(e.g., a plate line 215, a plate component 145) coupled with therespective memory cell 105 to the ground voltage. In some examples,equalizing the bias across a respective one of the memory cells 105 mayinclude biasing a digit line 210 that is coupled with the respectivememory cell 105 to a non-zero voltage and biasing a common node (e.g., aplate line 215, a plate component 145) coupled with the respectivememory cell 105 to the non-zero voltage. In some examples, equalizingthe bias across a respective one of the memory cells 105 may includecoupling a digit line 210 coupled with the respective memory cell 105and a common node (e.g., a plate line 215, a plate component 145)coupled with the respective memory cell 105 to a same voltage source(e.g., a chassis ground, a ground voltage source, an equalizationvoltage source).

The operations of 510 and 511 described with reference to the timingdiagram 500 of FIG. 5 may illustrate an example of a voltage adjustmentoperation where each of the word lines 205-a of the first memory section110-b are activated simultaneously (e.g., at 510) and deactivatedsimultaneously (e.g., at 511). However, in other examples, activation ordeactivation of word lines 205 in a voltage adjustment operation of amemory section 110 may occur in different orders or arrangements. Forexample, various voltage adjustment operations may include activating ordeactivating each of the word lines 205 or cell selection components 230of a selected memory section 110 concurrently or simultaneously, oractivating or deactivating each of the set word lines 205 of theselected memory section 110 section according to a sequential word lineorder. In another example, a voltage adjustment operation may includeactivating a first subset of the of word lines 205 during a first timeperiod and activating a second subset of the word lines 205 during asecond time period that is different (e.g., starting at a differenttime, having a different duration, non-overlapping, overlapping) fromthe first time period.

For example, with reference to the circuit 400 of FIG. 4, to activateeach of the word lines 205-a of the first memory section 110-b in asequential order, the activation may include activating word line205-a-1, then activating word line 205-a-2, and so on, until activatingword line 205-a-n. The activations of such a sequential ordering mayoccur in time intervals that are overlapping (e.g., where the word line205-a-2 begins an activation before an activation of the word line205-a-1 is complete) or non-overlapping (e.g., where the word line205-a-2 begins an activation after an activation of the word line205-a-1 is complete). To deactivate all of the word lines 205-a of thefirst memory section 110-b, such a deactivation may also occur in asequential order, which may be the same as or different from anactivation order. Like the activations discussed above, thedeactivations of such a sequential ordering may also occur in timeintervals that are overlapping (e.g., where the word line 205-a-2 beginsa deactivation before a deactivation of the word line 205-a-1 iscomplete) or non-overlapping (e.g., where the word line 205-a-2 begins adeactivation after a deactivation of the word line 205-a-1 is complete).

In some examples in accordance with the present disclosure, a voltageadjustment operation may combine the activation or selection of wordlines 205 with an activation or selection of digit lines 210. Forexample, when a memory device 100 has multiple levels or other subsetsof digit lines 210 of a memory section 110 that may be selected with alevel selection component or column selection component, the levels orother subsets of digit lines 210 of the memory section 110 may also beselected or activated as part of a voltage adjustment operation. In someexamples, the levels or other subsets of digit lines 210 of the memorysection 110 may each be selected or activated according to a sequentialorder, and may be selected or activated (e.g., iterated through,switched between) at a same rate or different rate as an activation ofword lines 205 of the operation.

In one example, a voltage adjustment operation may be performedaccording to a “WL-fast, DL-slow” activation configuration. In otherwords, the described operations may cycle through activating word lines205 relatively quickly, and digit lines 210 or sets of digit lines 210relatively slowly. In one example, a voltage adjustment operation mayinclude activating each of the word lines 205 or rows of a first level(e.g., subset of digit lines 210, subset of columns), then activatingeach of the word lines 205 or rows of a second level, and so on. Inexamples where different subsets of digit lines 210 or different subsetsof columns share common word lines, a voltage adjustment operation mayinclude cycling through activations of each of the common word lines 205while a first subset of digit lines 210 or subset of columns isactivated, then repeating the cycling through activations of each of thecommon word lines 205 while a second subset of digit lines 210 or subsetof columns is activated, and so on, until activating each of the commonword lines 205 while a last subset of digit lines 210 or subset ofcolumns is activated. Other examples are possible, such as a voltageadjustment operation performed according to a “DL-fast, WL-slow”activation configuration.

Following the operations of 615, the method 600-a may return to 610 fora determination to perform a subsequent voltage adjustment operation,and subsequent selection of a memory section 110 for the voltageadjustment operation. In other words, a memory device 100 may cyclebetween the operations of 610 and 615 in an iterative manner to performvoltage adjustment operations throughout the operation of the memorydevice 100. Following the operations of 615, or as part of theoperations of 615, a voltage adjustment timer or counter may be reset,such that the timer or counter may accumulate time or counts over a newvoltage adjustment interval prior to repeating the operations of 610. Inother words, after performing the operations of 615, returning to 610may be based on or triggered by a value of a voltage adjustmentoperation timer or counter.

At each iteration, a counter of access operations for the selectedmemory section 110 (e.g., the memory section 110 on which the voltageadjustment operation was performed at 615) may be reset to zero, whilethe counters of access operations for other memory sections 110 maycontinue accumulating counts of access operations. In other words, whena voltage adjustment operation is performed on a most-frequentlyaccessed memory section 110 at 615, a different memory section 110 maybecome the most-frequently accessed memory section immediately followingthe operations of 615.

The method 600-b may be another example of performing a voltageadjustment operation (e.g., a dissipation operation, an equalizationoperation) in accordance with examples of the present disclosure. Themethod 600-b illustrates examples of variations that may be included ina voltage adjustment operation, and may include other variations of avoltage adjustment operation described with reference to the method600-a that are not repeated below.

At 655, the method 600-b may include determining a quantity of accessoperations performed on each of a plurality of memory sections 110 of amemory device 100. For example, one or more memory controllers 170 mayhave a storage component that, for each of a set of memory sections 110,tracks a number of access operations performed on the respective memorysection 110. As used herein, a set of memory sections 110 may refer toall of the memory sections 110 of a memory device 100, all of the memorysections 110 of a particular subset of memory sections 110 of a memorydevice 100, all of the memory sections 110 of a particular bank ofmemory sections 110 of a memory device 100, or other sets of memorysections 110 (e.g., sets of memory sections 110 that may supportperforming separate instances of the method 600-a or 600-b).

At 660 the method 600-b may include selecting one of the sections (e.g.,one of the memory sections 110 of the memory device 100) for anequalization operation based on the determined quantity of accessoperations performed on each of the memory sections 110. For example,referring to components of the circuit 400, at 660 the memory controller170-b may determine to perform an equalization operation (e.g., of amemory device 100 that includes the circuit 400) on either the firstmemory section 110-b or the second memory section 110-c based on whichof the memory sections 110 has been most-frequently accessed (e.g., amemory section 110 associated with a highest value of an incrementedcounter of access operations, a memory section 110 having been accessedmost-frequently since a prior equalization operation on the respectivememory section 110).

In some examples, the operations of 660 may be based on or triggered bya timer, a counter, or some other determination or indication ofperiodic or aperiodic interval. In some examples, the operations of 660may be based on or triggered by a different type of counter, such as acounter that tracks a total number of access operations performed on amemory device 100 or a bank of a memory device 100. In some examples,the operations at 610 may include determining to select one of thememory sections 110 for an equalization operation based on a totalnumber of access operations performed on the memory device (e.g., sincea prior equalization operation was performed). In other words, in someexamples, the section selection operations of 660 may be based on ortriggered by a determined quantity of access operations of a memorydevice 100.

At 665 the method 600-b may include performing an equalization operationon the selected section (e.g., a most-frequently accessed memory section110). For example, at 665, the memory device 100 may perform aspects ofthe operations of 510 and 511 described with reference to the timingdiagram 500 of FIG. 5 and the circuit 400 of FIG. 4. (e.g., selecting oractivating word lines of the selected memory section 110, equalizing abias across memory cells 105 of the memory section 110). In other words,in some examples, the operations of 660 described with reference tomethod 600-b (e.g., selecting a memory section 110 for an equalizationoperation) may occur between the operations of 509 and 510 describedwith reference to timing diagram 500 (e.g., after performing one or moreaccess operations on a memory cell 105 of a memory section 110, beforeperforming an equalization operation). Thus, in some examples theoperations of 660 may refer to a decision or trigger to perform theoperations of 509 and 510 of the timing diagram 500.

Following the operations of 665, the method 600-b may return to 660 fora determination to perform a subsequent equalization operation, andsubsequent selection of a memory section 110 for the equalizationoperation. In other words, a memory device 100 may cycle between theoperations of 660 and 665 in an iterative manner to perform equalizationoperations throughout the operation of the memory device 100. Followingthe operations of 665, or as part of the operations of 665, anequalization timer or counter may be reset, such that the timer orcounter may accumulate time or counts over a new equalization intervalprior to repeating the operations of 660. In other words, afterperforming the operations of 665, returning to 660 may be based on ortriggered by a value of an equalization operation timer or counter.

At each iteration, a counter of access operations for the selectedmemory section 110 (e.g., the memory section 110 on which theequalization operation was performed at 665) may be reset to zero, whilethe counters of access operations for other memory sections 110 maycontinue accumulating counts of access operations. In other words, whenan equalization operation is performed on a most-frequently accessedmemory section 110 at 665, a different memory section 110 may become themost-frequently accessed memory section immediately following theoperations of 665.

In some examples, a memory device 100 may perform a first instance ofthe method 600-a or 600-b for a first set of memory sections 110 (e.g.,a first bank of a memory device 100), while also performing a secondinstance of the method 600-a or 600-b for a second set of memorysections 110 (e.g., a second bank of the memory device 100), where thefirst and second instances may be performed according to the sameapproach or configuration, or a different approach or configurations. Insuch examples, the performance of respective voltage adjustmentoperations of different voltage adjustment cycles or intervals may occursimultaneously, according to the same voltage adjustment intervals butstaggered so that respective voltage adjustment operations do not occursimultaneously, or according to different voltage adjustment intervals.In some examples, a memory controller 170 may perform a first voltageadjustment cycle based on selecting most-frequently accessed memorysections 110 in order to limit leakage charge accumulation ofheavily-accessed memory sections, and also perform a second voltageadjustment cycle according to a sequential memory section order in orderto perform voltage adjustment operations on respective memory sections110 at least once in a given maximum voltage adjustment interval (e.g.,to set or define a maximum time between voltage adjustment operations ona given memory section 110).

In some examples, voltage adjustment operations may be scheduled tooccur at intervals (e.g., periodic section selection intervals,aperiodic section selection intervals), but may be canceled oroverridden if an access operation (e.g., one or more access operationsusing the word lines 205 associated with the voltage adjustmentoperation) is being performed on a memory section 110 identified for avoltage adjustment operation.

It should be noted that the method and variations described aboveillustrate possible implementations, and that the operations and thesteps may be rearranged or otherwise modified, and that otherimplementations are possible in accordance with the present disclosure.Further, different instances of the described methods may be performed(e.g., by a same memory device) simultaneously, during overlapping timeperiods, or during non-overlapping time periods. In some examples,different instances of the described methods performed by a same memorydevice may include performing substantially the same method (e.g., ondifferent memory sections 110, on different sets of memory section 110)or performing substantially different methods (e.g., on different memorysections 110, on different sets of memory section 110).

FIG. 7 illustrates an example of a state diagram 750 that may be relatedto a state machine 700 where the state diagram and/or the state machinemay support access schemes for activity-based data protection in amemory device in accordance with various embodiments of the presentdisclosure. The state machine 700 and the state diagram 750 may be anexample for supporting the determination of a quantity of accessoperations performed on each of a plurality of memory sections 110 andselecting a memory section 110 for a voltage adjustment operation basedon the determined quantity of access operations.

The state machine 700 may be an example of a memory controller 170, ormay be included in or implemented by a memory controller 170. The statemachine 700 may receive signals or indications as inputs (e.g.,ACT_PULSE, PCH_PULSE, RFSH_PULSE, RESETF, SEC_ADD<4:0>) and transmit orotherwise convey signals or indications as outputs (e.g., SEC_REF<4:0>).Signals or indications may be received from a different portion of asame memory controller 170, or received from a different memorycontroller 170. Signals or indications may be provided or otherwiseconveyed to a different portion of a same memory controller 170, ortransmitted to a different memory controller 170. In some examples, thestate machine 700 may include a set of counters or registers (e.g.,section counters, a counter for each of a set of memory sections 110, acounter for each of a bank of memory sections 110) that track a numberof access operations performed on a given memory section 110 (e.g.,since a most-recent voltage adjustment operation on the given memorysection).

An input signal or indication ACT_PULSE may represent or indicatewhether a memory section 110 (e.g., of a set of memory sections 110, ofa bank of memory sections 110) is being activated or accessed. In someexamples the input signal or indication ACT_PULSE may be a generalsignal or indication that any one of a set of memory sections 110 isbeing accessed, or that a particular bank of memory sections 110 isbeing accessed (e.g., a bank-wide or bank-specific signal orindication).

An input signal or indication PCH_PULSE may represent or indicate that amemory section 110 (e.g., of a set of memory sections 110, of a bank ofmemory sections 110) is being precharged (e.g., that a plate line 215 orcommon plate is being raised, that another access line of a memorysection 110 is being biased). In some examples the input signal orindication PCH_PULSE may be a general signal or indication that any oneof a set of memory sections 110 is being precharged, or that aparticular bank of memory sections 110 is being precharged (e.g., abank-wide or bank-specific signal or indication)

An input signal or indication RFSH_PULSE may represent or indicate thata voltage adjustment operation (e.g., a dissipation operation, anequalization operation) is to be performed (e.g., on a memory section110 of a set of memory sections, on a memory section 110 of a bank ofmemory sections 110). In some examples, the input signal or indicationRFSH_PULSE may be based on or triggered by a voltage adjustment interval(e.g., a periodic interval, a determined duration of a timer, adetermined total quantity of access operations across a set of memorysections 110).

An input signal or indication RESETF may represent or indicate that thestate machine 700 is to be reset. For example, the input signal RESETFmay indicate that counters or registers associated with a number ofaccess operations performed on various memory sections 110 are to bereset.

An input signal or indication SEC_ADD<4:0> may represent or indicate amemory section 110 associated with a performed access operation (e.g.,accompanying the signal or indication ACT_PULSE, indicating a particularmemory section 110 associated with an access operation related to theinput signal or indication ACT_PULSE) or performed precharge operation(e.g., accompanying the signal or indication PCH_PULSE, indicating aparticular memory section 110 associated with a precharge operationrelated to the input signal or indication PCH_PULSE). In some examples,the input signal or indication SEC_ADD<4:0> may be a multi-bit value(e.g., a 5-bit value) to indicate one of 32 memory sections 110 (e.g.,of a bank of memory sections 110 associated with an access operation orprecharge operation).

An output signal or indication SEC_REF<4:0> may represent or indicate amost-frequently accessed memory section 110 (e.g., a memory section 110having the highest number of access operations performed since a priorvoltage adjustment operation on the respective memory section 110). Insome examples, the output signal or indication SEC_REF<4:0> may be amulti-bit value (e.g., a 5-bit value) to indicate one of 32 memorysections 110 (e.g., a memory section 110 of a memory bank having ahighest number of access operations since a prior voltage adjustmentoperation, a memory section 110 of a memory bank to be associated with anext voltage adjustment operation of the memory bank).

The state diagram 750 may illustrate a set of states (e.g., state 760,state 770, state 780, state 790), and transitions between the set ofstates, that may be controlled or performed by the state machine 700.The state diagram 750 may also represent the determination or transitionof values for stored variables or values (e.g., of the state machine700) associated with the state diagram 750.

The state machine 700 may be initialized in state 760, which mayrepresent an idle state. The idle state of state 760 may illustrate anoperating state in which the state machine 700 does not performfunctions or determinations related to voltage adjustment operations. Invarious examples the state machine 700 may transition to the state 770upon receiving or processing an “ACT” signal or indication (e.g.,associated with an activated value of the input signal or indicationACT_PULSE), or the state machine 700 may transition to the state 790upon receiving or processing an “RFSH” signal or indication (e.g.,associated with an activated value of the input signal or indicationRFSH_PULSE).

At the state 770, (e.g., after receiving or processing an “ACT” signalor indication) the state machine may increment a counter or register ofone of the memory sections 110 (e.g., based at least in part on theinput signal or indication SEC_ADD<4:0>). In other words, at 770, thestate machine 700 may increment the counter or register of a memorysection 110 that is to be accessed (e.g., incrementing R(SX), where R isthe number of access performed on a section “SX” which may be the samesection address as provided by the signal or indication SEC_ADD<4:0>).

At the state 770, the state machine 700 may also perform a firstcomparison to redetermine a memory section 110 having a highest numberof access operations since a prior voltage adjustment operation (e.g.,redetermine a stored value of the output signal or indication SEC_REF).In other words, at 770, the state machine 700 may determine the newaddress of a memory section 110 (e.g., a newly determined orto-be-determined SEC_REF) with the highest number of access operationsas being either the previously-determined memory section 110 having thehighest number of access operations (e.g., a current orpreviously-determined SEC_REF) or a memory section 110 that previouslyhad a second-highest number of access operations, which may be known as“CHALLENGER.” Performing the comparison in this manner may require fewercomparison operations or comparator elements of a circuit than if eachof the memory sections 110 were ranked or compared at the state 770. Thestate machine 700 may transition from the state 770 to the state 780upon receiving or processing a “PCH” signal or indication (e.g.,associated with an activated value of the input signal or indicationPCH_PULSE).

At the state 780, (e.g., after receiving or processing an “PCH” signalor indication) the state machine may perform a second comparison toredetermine a memory section 110 having a highest number of accessoperations since a prior voltage adjustment operation (e.g., redeterminea stored value of the output signal or indication SEC_REF). In otherwords, at 780, the state machine 700 may determine the new address of amemory section 110 (e.g., a newly determined or to-be-determinedSEC_REF) with the highest number of access operations as being eitherthe previously-determined memory section 110 having the highest numberof access operations (e.g., a current or previously-determined SEC_REF)or a memory section 110 that has just been accessed (e.g., based atleast in part on the input signal or indication SEC_ADD<4:0>).Performing the comparison in this manner may require fewer comparisonoperations or comparator elements of a circuit than if each of thememory sections 110 were ranked or compared at the state 780.

At the state 780, the state machine 700 may also update the storedsection address of the memory section 110 having the second-highestnumber of access operations performed since a voltage adjustmentoperation (e.g., updating the stored section address for CHALLENGER).The state machine 700 may transition from the state 780 to the state 760(e.g., return to an idle state) upon determining the address of thememory section 110 having the highest number of access operations (e.g.,SEC_REF) and updating the address of the memory section 110 having thesecond-highest number of access operations (e.g., CHALLENGER).

At the state 790, (e.g., after receiving or processing an “RFSH” signalor indication) the state machine may clear a counter or register of thememory section 110 having a highest number of access operations (e.g., apreviously determined SEC_REF, a memory section 110 upon which a voltageadjustment operation was performed). In other words, at 790, the statemachine 700 may reset the counter or register of a most-frequentlyaccessed memory section 110 after or based on performing a voltageadjustment operation on the most-frequently-accessed memory section 110(e.g., clearing R(SEC_REF), where R is the number of access performed ona section “SEC_REF”). These operations may be an example of resettingthe quantity of access operations performed on the selected memorysection 110 to zero based at least in part on performing a voltageadjustment operation.

At the state 790, the state machine 700 may also promote the secondmost-frequently accessed memory section 110 to being the most-frequentlyaccessed memory section. In other words, the section address SEC_REFassociated with the memory section 110 having the highest number ofaccess operations may be replaced with the section address for theCHALLENGER, because the counter or register for previously determinedSEC_REF was just reset (e.g., after or based on performing a voltageadjustment operation on that section. In other words, at state 790, thestate machine 700 may replace the stored section address of the variableSEC_REF with the stored section address of the variable CHALLENGER.

The state machine 700 may transition from the state 790 to the state 760(e.g., return to an idle state) upon clearing the address of the memorysection 110 having the highest number of access operations (e.g.,clearing R(SEC_REF)) and replacing the address of the memory section 110having the highest number of access operations (e.g., SEC_REF) with thesection address of the memory section 110 previously having the secondhighest number of access operations (e.g., CHALLENGER).

Thus, the state machine 700 and the state diagram 750 may illustrate anexample of accumulating or determining a quantity of access operationsperformed on memory sections 110 of a memory device 100 (e.g., of a setof memory sections 110, of a bank of memory sections 110), and selectingone of the memory sections 110 for a voltage adjustment operation (e.g.,a dissipation operation, an equalization operation) based on thedetermined quantity of access operations performed on each of thesections (e.g., selecting a memory section 110 having a highest numberof access operations since a prior voltage adjustment operation wasperformed on the respective memory section 110). For example, the statemachine 700 and the state diagram 750 may support selecting, for avoltage adjustment operation, a memory section 110 having a highestdetermined quantity of access operations performed (e.g., since a priorvoltage adjustment operation on the respective memory section 110).

FIG. 8 shows a block diagram 800 of a memory device 805 that may supportaccess schemes for activity-based data protection in a memory device inaccordance with various embodiments of the present disclosure. Thememory device 805 may be referred to as an electronic memory apparatus,and may be an example of a component of a memory device 100 as describedwith reference to FIG. 1.

The memory device 805 may include one or more memory cells 810, whichmay be an example of memory cells 105 (e.g., of a memory section 110)described with reference to FIGS. 1 through 7. The memory device 805 mayalso include a memory controller 815, a word line 820, a plate line 825,a sense component 835, and a digit line 840. These components may be inelectronic communication with each other and may perform one or more ofthe functions described herein in accordance with aspects of thedisclosure. In some cases, the memory controller 815 may include abiasing component 850 and a timing component 855.

The memory controller 815 may be in electronic communication with theword line 820, the plate line 825, the digit line 840, and the sensecomponent 835, which may be examples of a word line 205, a plate line215, a digit line 210, and a sense component 150 described withreference to FIGS. 1 through 7. In some examples, the memory device 805may also include a latch 845, which may be an example of an I/Ocomponent 160 as described herein. The components of the memory device805 may be in electronic communication with each other and may performembodiments of the functions described with reference to FIGS. 1 through7. In some cases, the sense component 835 or latch 845 may be componentsof memory controller 815.

In some examples, the digit line 840 may be in electronic communicationwith the sense component 835 (e.g., via a signal development component280, via a bypass line 270, as described herein) and a ferroelectriccapacitor of a memory cell 810. A memory cell 810 may be writable with alogic state (e.g., a first or second logic state). The word line 820 maybe in electronic communication with the memory controller 815 (e.g., arow decoder of the memory controller 815) and a cell selection componentof a memory cell 810 (e.g., a switching component, a transistor). Theplate line 825 may be in electronic communication with the memorycontroller 815 and a plate of the ferroelectric capacitor of a memorycell 810. The sense component 835 may be in electronic communicationwith the memory controller 815, the digit line 840, and the latch 845.In some examples, a common access line may provide the functions of asignal line and a reference line. The sense control line 865 may be inelectronic communication with the sense component 835 and the memorycontroller 815. These components may also be in electronic communicationwith other components, inside, or outside, or both of the memory device805, in addition to components not listed above, via other components,connections, or busses.

The memory controller 815 may be an example of a memory controller 170as described herein, and may be configured to activate the word line820, the plate line 825, or the digit line 840 by applying voltages tovarious nodes. For example, the biasing component 850 may be configuredto apply a voltage to operate the memory cell 810 to read or write thememory cell 810 as described above. In some examples, the memorycontroller 815 may include one or more of a row component 125, a columncomponent 135, or a plate component 145, or may otherwise perform one ormore operations described with reference to row components 125, columncomponents 135, or plate components 145, or may otherwise communicatewith a row component 125, a column component 135, a plate component 145,or a combination thereof, as described with reference to FIGS. 1 through7, which may enable the memory controller 815 to access one or morememory cells 810. The biasing component 850 may provide voltages (e.g.,voltage sources) for coupling with the memory cell 810. Additionally oralternatively, the biasing component 850 may provide voltages (e.g.,voltage sources) for the operation of the sense component 835 or thereference component 830.

In some cases, the memory controller 815 may perform one or more of itsoperations using the timing component 855. For example, the timingcomponent 855 may control the timing of the various word line selectionsor plate biasing, including timing for switching and voltage applicationto perform the memory functions, such as reading and writing, discussedherein (e.g., in accordance with operations described with reference totiming diagram 500 of FIG. 5). In some cases, the timing component 855may control the operations of the biasing component 850. In some cases,the timing component 855 may include a timer associated with memorysections 110 of the memory device 805.

The sense component 835 may compare a sense signal from the memory cell810 (e.g., via digit line 840) with a reference signal (e.g., from thereference component 830 via reference line 860, from the memory cell810). Upon determining the logic state, the sense component 835 may thenstore the output in the latch 845, where it may be used in accordancewith the operations of an electronic device that may include the memorydevice 805. The sense component 835 may include one or more amplifiersin electronic communication with the latch and the ferroelectric memorycell.

The memory controller 815, or its sub-components, may be implemented inhardware, code (e.g., software, firmware) executed by a processor, orany combination thereof. If implemented in code executed by a processor,the functions of the memory controller 815, or its sub-components, maybe executed by a general-purpose processor, a digital signal processor(DSP), an application-specific integrated circuit (ASIC), afield-programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described in thepresent disclosure.

The memory controller 815, or its sub-components, may be physicallylocated at various positions, including being distributed such thatportions of functions are implemented at different physical locations byone or more physical devices. In some examples, the memory controller815, or its sub-components, may be a separate and distinct component inaccordance with various embodiments of the present disclosure. In otherexamples, the memory controller 815, or its sub-components, may becombined with one or more other hardware components, including but notlimited to an I/O component, a transceiver, a network server, anothercomputing device, one or more other components described in the presentdisclosure, or a combination thereof in accordance with variousembodiments of the present disclosure. The memory controller 815 may bean example of the memory controller 1015 described with reference toFIG. 10.

In some examples, the memory controller 815, including any subcomponentsthereof, may support the described examples of access schemes foractivity-based data protection in the memory device 805. For example,the memory device 805 may include a plurality of memory cells 810coupled with the digit line 840 and the plate line 825. In someexamples, each of the plurality of memory cells 810 may include a cellselection component configured to selectively couple the respective oneof the plurality of memory cells with the digit line 840. The memorydevice may include a plurality of word lines 820, each coupled with thecell selection component of the respective one of the plurality ofmemory cells. The memory device 805 may also include a row decodercoupled with each of the plurality of word lines, which may be includedin the memory controller 815, or may be a separate component incommunication with the memory controller 815.

In accordance with embodiments of the present disclosure, the memorycontroller 815 may be operable to perform voltage adjustment operations(e.g., dissipation operations, equalization operation) on memorysections 110 of the memory device 805. In some examples, the memorycontroller 815 may perform such operations by causing the row decoder toactivate each of the word lines 820 of a selected memory section 110. Insome examples, the memory controller 815 may perform such operations byequalizing a bias across storage elements (e.g., ferroelectriccapacitors) of each of the memory cells 810 of the selected memorysection 110.

FIG. 9 shows a block diagram 900 of a memory controller 915 that maysupport access schemes for activity-based data protection in a memorydevice in accordance with various embodiments of the present disclosure.The memory controller 915 may be an example of a memory controller 170described with reference to FIG. 1 or a memory controller 815 describedwith reference to FIG. 8. The memory controller 915 may include abiasing component 920 and a timing component 925, which may be examplesof biasing component 850 and timing component 855 described withreference to FIG. 8. The memory controller 915 may also include avoltage selector 930, a memory cell selector 935, a sense controller940, and an access operation counter 945. Each of these modules maycommunicate, directly or indirectly, with one another (e.g., via one ormore buses).

The voltage selector 930 may initiate the selection of voltage sourcesto support various access operations of a memory device. For example,the voltage selector 930 may generate or trigger control signals used toactivate or deactivate various switching components or voltage sources,such as the control signals provided to row components 125, platecomponents 145, sense components 150, or reference components 285-a asdescribed with reference to FIGS. 1 through 5. For example, the voltageselector 930 may generate one or more of the logical signals forselecting (e.g., enabling, disabling) the voltages of word lines 205,digit lines 210, or plate lines 215 as illustrated in timing diagram 500of FIG. 5.

The memory cell selector 935 may select a memory cell for accessoperations (e.g., read operations, write operations, rewrite operations,refresh operations, voltage adjustment operations, equalizationoperations, dissipation operations). In some examples, the memory cellselector 935 may generate logical signals used to activate or deactivatea memory section 110 of a memory device. In some examples, the memorycell selector 935 may generate logical signals used to activate ordeactivate a cell selection component, such as cell selection components230 described with reference to FIGS. 2 through 5. In some examples, thememory cell selector 935 may initiate or otherwise control the word linevoltages V_(WL) illustrated in the timing diagram 500 of FIG. 5.

The sense controller 940 may control various operations of a sensecomponent, such as the sense components 150 described with reference toFIGS. 1 through 5. For example, the sense controller 940 may generatelogical signals (e.g., isolation signals) used to activate or deactivatea sense component isolation component, such as the switching componentsbetween a sense component 150 and a memory section 110 or referencecomponent 285 described with reference to FIGS. 4 and 5. In someexamples, the sense controller 940 may generate logical signals (e.g.,equalization signals) used to equalize nodes of a sense component 150 orof an access line. In some examples, the sense controller 940 maygenerate logical signals used to couple or decouple a sense componentwith a sensing voltage source, or to couple or decouple a sensecomponent with an input/output component 160 or a latch 845. Thus, insome examples, the sense controller 940 may generate the logical signalsdescribed with reference to the timing diagram 500 of FIG. 5.

In some embodiments, the sense controller 940 may compare a voltage of afirst node of a sense amplifier with a voltage of a second node of asense amplifier, where the voltages are based on (e.g., result from)accessing the memory cell with one or more access operations of a readoperation. The sense controller 940 may determine a logic valueassociated with the memory cell based on comparing the resultantvoltages. In some examples, the sense controller 940 may provide signalsto another component to determine the logic value associated with thememory cell.

The access operation counter 945 may accumulate or otherwise determine aquantity of access operations on each of a set of memory sections 110 ofa memory device. In some examples, the access operation counter 945 mayreset the quantity of access operations performed on the selectedsection to zero based at least in part on performing the voltageadjustment operation.

FIG. 10 shows a diagram of a system 1000 including a device 1005 thatmay support access schemes for activity-based data protection in amemory device in accordance with various embodiments of the presentdisclosure. The device 1005 may be an example of or include thecomponents of memory device 100 as described above, for example, withreference to FIG. 1. The device 1005 may include components forbi-directional communications including components for transmitting andreceiving communications, including a memory controller 1015, memorycells 1020, a basic input/output system (BIOS) component 1025, aprocessor 1030, an I/O component 1035, and peripheral components 1040.These components may be in electronic communication via one or morebusses (e.g., bus 1010).

The memory controller 1015 may operate one or more memory cells asdescribed herein. Specifically, the memory controller 1015 may beconfigured to support the described sensing schemes for accessing memorycells, or performing voltage adjustment operations. In some cases, thememory controller 1015 may include a row component, a column component,a plate component, or a combination thereof, as described with referenceto FIGS. 1 through 5.

The memory cells 1020 may be an example of memory cells 105 or 810described with reference to FIGS. 1 through 8, and may store information(e.g., in the form of a logic state) as described herein.

The BIOS component 1025 be a software component that includes BIOSoperated as firmware, which may initialize and run various hardwarecomponents. The BIOS component 1025 may also manage data flow between aprocessor and various other components, such as peripheral components,I/O control components, and others. The BIOS component 1025 may includea program or software stored in read only memory (ROM), flash memory, orany other non-volatile memory.

The processor 1030 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a central processing unit (CPU), amicrocontroller, an ASIC, an FPGA, a programmable logic device, adiscrete gate or transistor logic component, a discrete hardwarecomponent). In some cases, the processor 1030 may be configured tooperate a memory array using a memory controller. In other cases, amemory controller may be integrated into the processor 1030. Theprocessor 1030 may be configured to execute computer-readableinstructions stored in a memory to perform various functions (e.g.,functions or tasks supporting access schemes for activity-based dataprotection in a memory device).

The I/O component 1035 may manage input and output signals for thedevice 1005. The I/O component 1035 may also manage peripherals notintegrated into the device 1005. In some cases, the I/O component 1035may represent a physical connection or port to an external peripheral.In some cases, the I/O component 1035 may utilize an operating systemsuch as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, oranother known operating system. In other cases, the I/O component 1035may represent or interact with a modem, a keyboard, a mouse, atouchscreen, or a similar device. In some cases, the I/O component 1035may be implemented as part of a processor. In some cases, a user mayinteract with the device 1005 via the I/O component 1035 or via hardwarecomponents controlled by the I/O component 1035. The I/O component 1035may support accessing the memory cells 1020, including receivinginformation associated with the sensed logic state of one or more of thememory cells 1020, or providing information associated with writing alogic state of one or more of the memory cells 1020.

The peripheral components 1040 may include any input or output device,or an interface for such devices. Examples may include disk controllers,sound controller, graphics controller, Ethernet controller, modem,universal serial bus (USB) controller, a serial or parallel port, orperipheral card slots, such as peripheral component interconnect (PCI)or accelerated graphics port (AGP) slots.

The input 1045 may represent a device or signal external to the device1005 that provides input to the device 1005 or its components. This mayinclude a user interface or an interface with or between other devices.In some cases, the input 1045 may be managed by the I/O component 1035,and may interact with the device 1005 via a peripheral component 1040.

The output 1050 may represent a device or signal external to the device1005 configured to receive output from the device 1005 or any of itscomponents. Examples of the output 1050 may include a display, audiospeakers, a printing device, another processor or printed circuit board,or other devices. In some cases, the output 1050 may be a peripheralelement that interfaces with the device 1005 via the peripheralcomponent(s) 1040. In some cases, the output 1050 may be managed by theI/O component 1035.

The components of the device 1005 may include circuitry designed tocarry out their functions. This may include various circuit elements,for example, conductive lines, transistors, capacitors, inductors,resistors, amplifiers, or other active or inactive elements, configuredto carry out the functions described herein. The device 1005 may be acomputer, a server, a laptop computer, a notebook computer, a tabletcomputer, a mobile phone, a wearable electronic device, a personalelectronic device, or the like. Or the device 1005 may be a portion orelement of such a device.

The description herein provides examples, and is not limiting of thescope, applicability, or examples set forth in the claims. Changes maybe made in the function and arrangement of elements discussed withoutdeparting from the scope of the disclosure. Some examples may omit,substitute, or add various operations, procedures, or components asappropriate. Also, features described with respect to some examples maybe combined in other examples.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the above description may berepresented by voltages, currents, electromagnetic waves, magneticfields or particles, optical fields or particles, or any combinationthereof. Some drawings may illustrate signals as a single signal;however, it will be understood by a person of ordinary skill in the artthat the signal may represent a bus of signals, where the bus may have avariety of bit widths.

As used herein, the term “virtual ground” refers to a node of anelectrical circuit that is held at a voltage of approximately zero volts(0V), or more generally represents a reference voltage of the electricalcircuit or device including the electrical circuit, which may or may notbe directly coupled with ground. Accordingly, the voltage of a virtualground may temporarily fluctuate and return to approximately 0V, orvirtual 0V, at steady state. A virtual ground may be implemented usingvarious electronic circuit elements, such as a voltage dividerconsisting of operational amplifiers and resistors. Otherimplementations are also possible. “Virtual grounding” or “virtuallygrounded” means connected to approximately 0V, or some other referencevoltage of a device.

The term “electronic communication” and “coupled” refers to arelationship between components that supports electron flow between thecomponents. This may include a direct connection or coupling betweencomponents or may include intermediate components. In other words,components that are “connected with” or “coupled with” are in electroniccommunication with each other. Components in electronic communicationmay be actively exchanging electrons or signals (e.g., in an energizedcircuit) or may not be actively exchanging electrons or signals (e.g.,in a de-energized circuit) but may be configured and operable toexchange electrons or signals upon a circuit being energized. By way ofexample, two components physically connected or coupled via a switch(e.g., a transistor) are in electronic communication regardless of thestate of the switch (e.g., open, closed).

The phrase “coupled between” may refer to an order of components inrelation to each other, and may refer to an electrical coupling. In oneexample, a component “B” that is electrically coupled between acomponent “A” and a component “C” may refer to an order of components of“A-B-C” or “C-B-A” in an electrical sense. In other words, electricalsignals (e.g., voltage, charge, current) may be passed from component Ato component C by way of component B.

A description of a component B being “coupled between” component A andcomponent C should not necessarily be interpreted as precluding otherintervening components in the described order. For example, a component“D” may be coupled between the described component A and component B(e.g., referring to an order of components of “A-D-B-C” or “C-B-D-A” asexamples), while still supporting component B being electrically coupledbetween component A and component C. In other words, the use of thephrase “coupled between” should not be construed as necessarilyreferencing an exclusive sequential order.

Further, a description of component B being “coupled between” componentA and component C does not preclude a second, different coupling betweencomponent A and component C. For example, component A and component Cmay be coupled with each other in a separate coupling that iselectrically parallel with a coupling via component B. In anotherexample, component A and component C may be coupled via anothercomponent “E” (e.g., component B being coupled between component A andcomponent C and component E being coupled between component A andcomponent C). In other words, the use of the phrase “coupled between”should not be construed as an exclusive coupling between components.

The term “isolated” refers to a relationship between components in whichelectrons are not presently capable of flowing between them; componentsare isolated from each other if there is an open circuit between them.For example, two components physically coupled by a switch may beisolated from each other when the switch is open.

As used herein, the term “shorting” refers to a relationship betweencomponents in which a conductive path is established between thecomponents via the activation of a single intermediary component betweenthe two components in question. For example, a first component shortedto a second component may exchange electrons with the second componentwhen a switch between the two components is closed. Thus, shorting maybe a dynamic operation that enables the application of voltage and/orflow of charge between components (or lines) that are in electroniccommunication.

As used herein, the term “electrode” may refer to an electricalconductor, and in some cases, may be employed as an electrical contactto a memory cell or other component of a memory array. An electrode mayinclude a trace, wire, conductive line, conductive layer, or the likethat provides a conductive path between elements or components of memorydevice 100.

As used herein, the term “terminal” need not suggest a physical boundaryor connection point of a circuit element. Rather, “terminal” may referto a reference point of a circuit relevant to the circuit element, whichmay also be referred to as a “node” or “reference point.”

As used herein, the term “layer” may refer to a stratum or sheet of ageometrical structure. each layer may have three dimensions (e.g.,height, width, and depth) and may cover some or all of a surface. Forexample, a layer may be a three-dimensional structure where twodimensions are greater than a third, such as a thin-film. Layers mayinclude different elements, components, and/or materials. In some cases,one layer may be composed of two or more sublayers. In some of theappended figures, two dimensions of a three-dimensional layer aredepicted for purposes of illustration. Those skilled in the art will,however, recognize that the layers are three-dimensional in nature.

Chalcogenide materials may be materials or alloys that include at leastone of the elements S, Se, and Te. Phase change materials discussedherein may be chalcogenide materials. Chalcogenide materials may includealloys of S, Se, Te, Ge, As, Al, Sb, Au, indium (In), gallium (Ga), tin(Sn), bismuth (Bi), palladium (Pd), cobalt (Co), oxygen (O), silver(Ag), nickel (Ni), platinum (Pt). Example chalcogenide materials andalloys may include, but are not limited to, Ge—Te, In—Se, Sb—Te, Ga—Sb,In—Sb, As—Te, Al—Te, Ge—Sb—Te, Te—Ge—As, In—Sb—Te, Te—Sn—Se, Ge—Se—Ga,Bi—Se—Sb, Ga—Se—Te, Sn—Sb—Te, In—Sb—Ge, Te—Ge—Sb—S, Te—Ge—Sn—O,Te—Ge—Sn—Au, Pd—Te—Ge—Sn, In—Se—Ti—Co, Ge—Sb—Te—Pd, Ge—Sb—Te—Co,Sb—Te—Bi—Se, Ag—In—Sb—Te, Ge—Sb—Se—Te, Ge—Sn—Sb—Te, Ge—Te—Sn—Ni,Ge—Te—Sn—Pd, or Ge—Te—Sn—Pt. The hyphenated chemical compositionnotation, as used herein, indicates the elements included in aparticular compound or alloy and is intended to represent allstoichiometries involving the indicated elements. For example, Ge—Te mayinclude Ge_(x)Te_(y), where x and y may be any positive integer. Otherexamples of variable resistance materials may include binary metal oxidematerials or mixed valence oxide including two or more metals, such as,transition metals, alkaline earth metals, and/or rare earth metals.Examples are not limited to a particular variable resistance material ormaterials associated with the memory elements of the memory cells. Forexample, other examples of variable resistance materials can be used toform memory elements and may include chalcogenide materials, colossalmagnetoresistive materials, or polymer-based materials, among others.

The devices discussed herein, including memory device 100, circuit 200,and circuit 400, described with reference to FIGS. 1, 2, and 4, may beformed on a semiconductor substrate, such as silicon, germanium,silicon-germanium alloy, gallium arsenide, gallium nitride, etc. In somecases, the substrate is a semiconductor wafer. In other cases, thesubstrate may be a silicon-on-insulator (SOI) substrate, such assilicon-on-glass (SOG) or silicon-on-sapphire (SOP), or epitaxial layersof semiconductor materials on another substrate. The conductivity of thesubstrate, or sub-regions of the substrate, may be controlled throughdoping using various chemical species including, but not limited to,phosphorous, boron, or arsenic. Doping may be performed during theinitial formation or growth of the substrate, by ion-implantation, or byany other doping means.

A transistor or transistors discussed herein may represent afield-effect transistor (FET) and comprise a three terminal deviceincluding a source, drain, and gate. The terminals may be connected toother electronic elements through conductive materials, such as metals.The source and drain may be conductive and may comprise a heavily-doped,or degenerate semiconductor region. The source and drain may beseparated by a lightly-doped semiconductor region or channel. If thechannel is n-type (e.g., majority carriers are electrons), then the FETmay be referred to as a n-type FET. If the channel is p-type (e.g.,majority carriers are holes), then the FET may be referred to as ap-type FET. The channel may be capped by an insulating gate oxide. Thechannel conductivity may be controlled by applying a voltage to thegate. For example, applying a positive voltage or negative voltage to ann-type FET or a p-type FET, respectively, may result in the channelbecoming conductive. A transistor may be “on” or “activated” when avoltage greater than or equal to the transistor's threshold voltage isapplied to the transistor gate. The transistor may be “off” or“deactivated” when a voltage less than the transistor's thresholdvoltage is applied to the transistor gate.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, well-known structures and devices are shownin block diagram form to avoid obscuring the concepts of the describedexamples.

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, an FPGA or other programmablelogic device, discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed herein. A general-purpose processor may be a microprocessor,but in the alternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices (e.g., a combinationof a digital signal processor (DSP) and a microprocessor, multiplemicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described above can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations. Also, as used herein, including in the claims, “or” as usedin a list of items (for example, a list of items prefaced by a phrasesuch as “at least one of” or “one or more of”) indicates an inclusivelist such that, for example, a list of at least one of A, B, or C meansA or B or C or AB or AC or BC or ABC (e.g., A and B and C).

As used herein, the term “substantially” means that the modifiedcharacteristic (e.g., a verb or adjective modified by the term“substantially”) need not be absolute but is close enough so as toachieve the advantages of the characteristic, or close enough that thecharacteristic referred to is true in the context of the relevantaspects of the disclosure.

As used herein, the phrase “based on” shall not be construed as areference to a closed set of conditions. For example, an exemplary stepthat is described as “based on condition A” may be based on both acondition A and a condition B without departing from the scope of thepresent disclosure. In other words, as used herein, the phrase “basedon” shall be construed in the same manner as the phrase “based at leastin part on.”

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other variations withoutdeparting from the scope of the disclosure. Thus, the disclosure is notlimited to the examples and designs described herein, but is to beaccorded the broadest scope consistent with the principles and novelfeatures disclosed herein.

1. (canceled)
 2. A method, comprising: determining to perform anequalization operation at a memory device based at least in part on aquantity of access operations performed on a plurality of sections ofthe memory device; selecting, based at least in part on determining toperform the equalization operation, a section from the plurality ofsections based at least in part on a quantity of access operationsperformed on the selected section; and performing the equalizationoperation based at least in part on selecting the section from theplurality of sections, wherein performing the equalization operationcomprises equalizing a bias across each memory cell of a plurality ofmemory cells of the selected section.
 3. The method of claim 2, whereinperforming the equalization operation comprises: biasing each word lineof a plurality of word lines of the selected section, each word line ofthe plurality of word lines configured to activate cell selectioncomponents of a respective row of the plurality of memory cells of theselected section.
 4. The method of claim 3, wherein the biasingcomprises: biasing each word line of the plurality of word lines with afirst voltage that is smaller than a second voltage used to access theword line during an access operation.
 5. The method of claim 3, whereinthe biasing comprises: biasing each word line of the plurality of wordlines with a first slew rate that is smaller than a second slew rateused to access the word line during an access operation.
 6. The methodof claim 2, wherein determining to perform the equalization operation isbased at least in part on an operating temperature of the memory device.7. The method of claim 2, wherein determining to perform theequalization operation is based at least in part on an access rate ofthe memory device.
 8. The method of claim 2, wherein the quantity ofaccess operations performed on the plurality of sections corresponds toa quantity of write operations, or a quantity of read operations, or acombined quantity of read operations and write operations performed onthe plurality of sections since a previous equalization operation at thememory device.
 9. The method of claim 2, wherein the quantity of accessoperations performed on the plurality of sections corresponds to aquantity of precharge operations performed on the plurality of sectionssince a previous equalization operation at the memory device.
 10. Themethod of claim 2, wherein the quantity of access operations performedon the selected section corresponds to a quantity of write operations,or a quantity of read operations, or a combined quantity of readoperations and write operations performed on the selected section sincea previous equalization operation performed on the selected section. 11.The method of claim 2, wherein the quantity of access operationsperformed on the selected section corresponds to a quantity of prechargeoperations performed on the selected section since a previousequalization operation performed on the selected section.
 12. Anapparatus comprising: a plurality of sections of a memory device, eachsection of the plurality of sections associated with a respectiveplurality of memory cells; and a controller operable to: determine toperform an equalization operation based at least in part on a quantityof access operations performed on the plurality of sections; select,based at least in part on the determination to perform the equalizationoperation, a section from the plurality of sections based at least inpart on a quantity of access operations performed on the selectedsection; and perform the equalization operation based at least in parton the selection of the section from the plurality of sections, whereinperforming the equalization operation comprises equalizing a bias acrosseach memory cell of the respective plurality of memory cells of theselected section.
 13. The apparatus of claim 12, wherein, to perform theequalization operation, the controller is operable to: bias each wordline of a plurality of word lines of the selected section, each wordline configured to activate cell selection components of a respectiverow of the respective plurality of memory cells of the selected section.14. The apparatus of claim 13, wherein, to bias each word line of theplurality of word lines, the controller is operable to: bias each wordline of the plurality of word lines with a first voltage that is smallerthan a second voltage used to access the word line during an accessoperation.
 15. The apparatus of claim 14, wherein the second voltage isassociated with a cell selection voltage for a read operation, a writeoperation, a rewrite operation, or a refresh operation.
 16. Theapparatus of claim 13, wherein, to bias each word line of the pluralityof word lines, the controller is operable to: bias each word line of theplurality of word lines with a first slew rate that is smaller than asecond slew rate used to access the word line during an accessoperation.
 17. The apparatus of claim 12, wherein the controller isoperable to: determine to perform the equalization operation based atleast in part on an operating temperature of the memory device.
 18. Theapparatus of claim 12, wherein the controller is operable to: determineto perform the equalization operation is based at least in part on anaccess rate of the memory device.
 19. The apparatus of claim 12,wherein: the quantity of access operations performed on the plurality ofsections corresponds to a quantity of write operations, or a quantity ofread operations, or a combined quantity of read operations and writeoperations performed on the plurality of sections since a previousequalization operation at the memory device; and the quantity of accessoperations performed on the selected section corresponds to a quantityof write operations, or a quantity of read operations, or a combinedquantity of read operations and write operations performed on theselected section since a previous equalization operation performed onthe selected section.
 20. The apparatus of claim 12, wherein: thequantity of access operations performed on the plurality of sectionscorresponds to a quantity of precharge operations performed on theplurality of sections since a previous equalization operation at thememory device; and the quantity of access operations performed on theselected section corresponds to a quantity of precharge operationsperformed on the selected section since a previous equalizationoperation performed on the selected section.
 21. A method, comprising:determining to perform a voltage adjustment operation at a memory devicebased at least in part on a quantity of access operations performed on aplurality of sections of the memory device; selecting, based at least inpart on determining to perform the voltage adjustment operation, asection from the plurality of sections based at least in part on aquantity of access operations performed on the selected section; andperforming the voltage adjustment operation based at least in part onselecting the section from the plurality of sections.